Nicotinamide is a potent inducer of endocrine differentiation in cultured human fetal pancreatic cells

Tankyrase inhibition promotes endocrine commitment of hPSC-derived pancreatic progenitors

Human pluripotent stem cells (hPSCs) have the potential to differentiate into various cell types, including pancreatic insulin-producing β cells, which are crucial for developing therapies for diabetes. However, current methods for directing hPSC differentiation towards pancreatic β-like cells are often inefficient and produce cells that do not fully resemble the native counterparts. Here, we report that highly selective tankyrase inhibitors, such as WIKI4, significantly enhances pancreatic differentiation from hPSCs. Our results show that WIKI4 promotes the formation of pancreatic progenitors that give rise to islet-like cells with improved β-like cell frequencies and glucose responsiveness compared to our standard cultures. These findings not only advance our understanding of pancreatic development, but also provide a promising new tool for generating pancreatic cells for research and potential therapeutic applications.

From iPSCs to Pancreatic β Cells: Unveiling Molecular Pathways and Enhancements with Vitamin C and Retinoic Acid in Diabetes Research

Diabetes mellitus, a chronic and non-transmissible disease, triggers a wide range of micro- and macrovascular complications. The differentiation of pancreatic β-like cells (PβLCs) from induced pluripotent stem cells (iPSCs) offers a promising avenue for regenerative medicine aimed at treating diabetes. Current differentiation protocols strive to emulate pancreatic embryonic development by utilizing cytokines and small molecules at specific doses to activate and inhibit distinct molecular signaling pathways, directing the differentiation of iPSCs into pancreatic β cells. Despite significant progress and improved protocols, the full spectrum of molecular signaling pathways governing pancreatic development and the physiological characteristics of the differentiated cells are not yet fully understood. Here, we report a specific combination of cofactors and small molecules that successfully differentiate iPSCs into PβLCs. Our protocol has shown to be effective, with the resulting cells exhibiting key functional properties of pancreatic β cells, including the expression of crucial molecular markers (pdx1, nkx6.1, ngn3) and the capability to secrete insulin in response to glucose. Furthermore, the addition of vitamin C and retinoic acid in the final stages of differentiation led to the overexpression of specific β cell genes.

Promoting β-cells function by the recapitulation of in vivo microenvironmental differentiation signals

The study aims to transdifferentiate rat bone marrow-derived mesenchymal stem cells (BM-MSCs) more efficiently into islet-like cells and encapsulate and transplant them with vital properties like stability, proliferation, and metabolic activity enhanced for the treatment of T1DM. Trans-differentiation of BM-MCs into islet-like cells induced by high glucose concentration combined with Nicotinamide, ꞵ-Mercaptoethanol, ꞵ-Cellulin, and IGF-1. Glucose challenge assays and gene expression profiles were used to determine functionality. Microencapsulation was performed using the vibrating nozzle encapsulator droplet method with a 1% alginate concentration. Encapsulated ꞵ-cells were cultured in a fluidized-bed bioreactor with 1850 μL/min fluid flow rates and a superficial velocity of 1.15 cm/min. The procedure was followed by transplanting transdifferentiated cells into the omentum of streptozotocin (STZ)-induced diabetic Wistar rats. Changes in weight, glucose, insulin, and C-peptide levels were monitored for 2 months after transplantation. PDX1, INS, GCG, NKx2.2, NKx6.1, and GLUT2 expression levels revealed the specificity of generated β-cells with higher viability (about 20%) and glucose sensitivity about twofold more. The encapsulated β-cells decreased the glucose levels in STZ-induced rats significantly (P < 0.05) 1 week after transplantation. Also, the weight and levels of insulin and C-peptide reached the control group. In contrast to the treated, the sham group displayed a consistent decline in weight and died when loss reached > 20% at day ~ 55. The coated cells secrete significantly higher amounts of insulin in response to glucose concentration changes. Enhanced viability and functionality of β-cells can be achieved through differentiation and culturing, a promising approach toward insulin therapy alternatives.

Tissue engineering approaches and generation of insulin-producing cells to treat type 1 diabetes

Tissue engineering (TE) has become a new effective solution to a variety of medical problems, including diabetes. Mesenchymal stem cells (MSCs), which have the ability to differentiate into endodermal and mesodermal cells, appear to be appropriate for this function. The purpose of this review was to evaluate the outcomes of various researches on the insulin-producing cells (IPCs) generation from MSCs with TE approaches to increase efficacy of type 1 diabetes treatments. The search was performed in PubMed/Medline, Scopus and Embase databases until 2021. Studies revealed that MSCs could also differentiate into IPCs under certain conditions. Therefore, a wide range of protocols have been used for this differentiation, but their effectiveness is very different. Scaffolds can provide a microenvironment that enhances the MSCs to IPCs differentiation, improves their metabolic activity and up-regulate pancreatic-specific transcription factors. They also preserve IPCs architecture and enhance insulin production as well as protect against cell death. This systematic review offers a framework for prospective research based on data. In vitro and in vivo evidence suggests that scaffold-based TE can improve the viability and function of IPCs.

[Imeglimin: features of the mechanism of action and potential benefits]

Imeglimin is the first drug in a new class of tetrahydrotriazine-containing oral hypoglycemic agents called «glimines». Its mechanism of action is aimed at achieving a double effect, firstly, to improve the function of beta cells of the pancreas, and secondly, to enhance the action of insulin in key tissues, including the liver and skeletal muscles. At the cellular level, imeglimin modulates mitochondrial function, which leads to an improvement in cellular energy metabolism, as well as to the protection of cells from death in conditions of excessive accumulation of reactive oxygen species. It is important to note that the mechanism of action of imeglimin differs from existing drugs used for the treatment of type 2 diabetes mellitus. Like glucagon-like peptide-1 receptor agonists, imeglimin enhances insulin secretion in an exclusively glucose-dependent manner, but their mechanism of action at the cellular level diverges. Sulfonylureas and glinides function by closing ATP-sensitive potassium channels to release insulin, which is also different from imeglimin. Compared with metformin, the effect of imeglimine is also significantly different. Other major classes of oral antihypertensive agents, such as sodium-glucose transporter-2 inhibitors, thiazolidinediones and α glucosidase inhibitors mediate their action through mechanisms that do not overlap with imeglimine. Given such differences in the mechanisms of action, imeglimin can be used as part of combination therapy, for example with sitagliptin and metformin. The imeglimine molecule is well absorbed (Tmax-4), and the half-life is 5-6 hours, is largely excreted through the kidneys, and also has no clinically significant interactions with either metformin or sitagliptin.

Pancreatic Duct Cells Isolated From Canines Differentiate Into Beta-Like Pancreatic Islet Cells

In this study, we isolated and cultured pancreatic ductal cells from canines and revealed the possibility for using them to differentiate into functional pancreatic beta cells in vitro. Passaged pancreatic ductal cells were induced to differentiate into beta-like pancreatic islet cells using a mixture of induced factors. Differentiated pancreatic ductal cells were analyzed based on intracellular insulin granules using transmission electron microscopy, the expression of insulin and glucagon using immunofluorescence, and glucose-stimulated insulin secretion using ELISA. Our data revealed that differentiated pancreatic ductal cells not only expressed insulin and glucagon but also synthesized insulin granules and secreted insulin at different glucose concentrations. Our study might assist in the development of effective cell therapies for the treatment of type 1 diabetes mellitus in dogs.

The Potential of Pancreatic Organoids for Diabetes Research and Therapy

The success of clinical transplantation of pancreas or isolated pancreatic islets supports the concept of cell-based cure for diabetes. One limitation is the shortage of cadaver human pancreata. The demand-supply gap could potentially be bridged by harnessing the self-renewal capacity of stem cells. Pluripotent stem cells and adult pancreatic stem cells have been explored as possible cell sources. Recently, a system for long-term culture of proposed adult pancreatic stem cells in a form of organoids was developed. Generated organoids partially mimic the architecture and cell-type composition of pancreatic tissue. Here, we review the attempts over the past decade, to utilize the organoid cell culture principles in order to identify, expand, and differentiate the adult pancreatic stem cells from different compartments of mouse and human pancreata. The development of the culture conditions, effects of specific growth factors and small molecules is discussed. The potential utility of the adult pancreatic stem cells is considered in the context of other cell sources.

Imeglimin preserves islet β-cell mass in Type 2 diabetic ZDF rats

Objectives

Type 2 diabetes (T2D) is driven by progressive dysfunction and loss of pancreatic β-cell mass. Imeglimin is a first-in-class novel drug candidate that improves glycaemia and glucose-stimulated insulin secretion in preclinical models and patients. Given evidence that imeglimin can attenuate β-cell dysfunction and protect β cells in vitro, we postulated that imeglimin could also exert longer term effects to prevent pancreatic β-cell death and preserve functional β-cell mass in vivo.

Methods

Zucker diabetic fatty (ZDF) male rats were treated by oral gavage with imeglimin at a standard dose of 150 mg/kg or vehicle, twice daily for five weeks. At treatment completion, oral glucose tolerance tests were performed in fasted animals before a thorough histomorphometry and immunohistochemical analysis was conducted on pancreas tissue slices to assess cellular composition and disease status.

Results

Imeglimin treatment significantly improved glucose-stimulated insulin secretion (augmentation of the insulinogenic index) and improved glycaemia. Both basal insulinaemia and pancreatic insulin content were also increased by imeglimin. In ZDF control rats, islet structure was disordered with few β-cells; after imeglimin treatment, islets appeared healthier with more normal morphology in association with a significant increase in insulin-positive β-cells. The increase in β-cell mass was associated with a greater degree of β-cell proliferation in the presence of reduced apoptosis. Unexpectedly, a decrease in as a α-cell mass was also documented due to an apparent antiproliferative effect of imeglimin on this cell type.

Conclusion

In male ZDF rats, chronic imeglimin treatment corrects a paramount component of type 2 diabetes progression: progressive loss of functional β-cell mass. In addition, imeglimin may also moderate a-cell turnover to further ameliorate hyperglycaemia. Cumulatively, these cellular effects suggest that imeglimin may provide for disease modifying effects to preserve functional β-cell mass.

Generation of high yield insulin-producing cells (IPCs) from various sources of stem cells

Type 1 diabetes mellitus occurs when beta cell mass is reduced to less than 20% of the normal level due to immune system destruction of beta cell resulting in an inability to secrete enough insulin. The prevalence of diabetes is expanding according to the American Diabetes Association and the World Health Organization (WHO), foretold to exceed 350 million by 2030. The current treatment does not cure many of the serious complications associated with the disease such as neuropathy, nephropathy, dyslipidemia, retinopathy and cardiovascular disease. Whole pancreas or isolated pancreatic islet transplantation as an alternative therapy can prevent or reduce some of the complications of diabetes. However, the shortage of matched organ or islets cells donor and alloimmune responses limit this therapeutic strategy. Recently, several reports have raised extremely promising results to use different sources of stem cells to differentiate insulin-producing cells and focus on the expansion of these alternative sources. Stem cells, due to their potential for multiple differentiation and self-renewal can differentiate into all cell types, including insulin-producing cells (IPCs). Generation of new beta cells can be achieved from various stem cell sources, including embryonic stem cells (ESCs), adult stem cells, such as mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs). Thus, this chapter discusses on the assistance of cellular reprogramming of various stem cells as candidates for the generation of IPCs using transcription factors/miRNA, cytokines/small molecules and tissue engineering.

Mechanism of action of Imeglimin: A novel therapeutic agent for type 2 diabetes

Imeglimin is an investigational first-in-class novel oral agent for the treatment of type 2 diabetes (T2D). Several pivotal phase III trials have been completed with evidence of statistically significant glucose lowering and a generally favourable safety and tolerability profile, including the lack of severe hypoglycaemia. Imeglimin's mechanism of action involves dual effects: (a) amplification of glucose-stimulated insulin secretion (GSIS) and preservation of β-cell mass; and (b) enhanced insulin action, including the potential for inhibition of hepatic glucose output and improvement in insulin signalling in both liver and skeletal muscle. At a cellular and molecular level, Imeglimin's underlying mechanism may involve correction of mitochondrial dysfunction, a common underlying element of T2D pathogenesis. It has been observed to rebalance respiratory chain activity (partial inhibition of Complex I and correction of deficient Complex III activity), resulting in reduced reactive oxygen species formation (decreasing oxidative stress) and prevention of mitochondrial permeability transition pore opening (implicated in preventing cell death). In islets derived from diseased rodents with T2D, Imeglimin also enhances glucose-stimulated ATP generation and induces the synthesis of nicotinamide adenine dinucleotide (NAD+ ) via the 'salvage pathway'. In addition to playing a key role as a mitochondrial co-factor, NAD+ metabolites may contribute to the increase in GSIS (via enhanced Ca++ mobilization). Imeglimin has also been shown to preserve β-cell mass in rodents with T2D. Overall, Imeglimin appears to target a key root cause of T2D: defective cellular energy metabolism. This potential mode of action is unique and has been shown to differ from that of other major therapeutic classes, including biguanides, sulphonylureas and glucagon-like peptide-1 receptor agonists.

Imeglimin amplifies glucose-stimulated insulin release from diabetic islets via a distinct mechanism of action

Pancreatic islet β-cell dysfunction is characterized by defective glucose-stimulated insulin secretion (GSIS) and is a predominant component of the pathophysiology of diabetes. Imeglimin, a novel first-in-class small molecule tetrahydrotriazine drug candidate, improves glycemia and GSIS in preclinical models and clinical trials in patients with Type 2 diabetes; however, the mechanism by which it restores β-cell function is unknown. Here, we show that imeglimin acutely and directly amplifies GSIS in islets isolated from rodents with Type 2 diabetes via a mode of action that is distinct from other known therapeutic approaches. The underlying mechanism involves increases in the cellular nicotinamide adenine dinucleotide (NAD+) pool-potentially via the salvage pathway and induction of nicotinamide phosphoribosyltransferase (NAMPT) along with augmentation of glucose-induced ATP levels. Further, additional results suggest that NAD+ conversion to a second messenger, cyclic ADP ribose (cADPR), via ADP ribosyl cyclase/cADPR hydrolase (CD38) is required for imeglimin's effects in islets, thus representing a potential link between increased NAD+ and enhanced glucose-induced Ca2+ mobilization which-in turn-is known to drive insulin granule exocytosis. Collectively, these findings implicate a novel mode of action for imeglimin that explains its ability to effectively restore-β-cell function and provides for a new approach to treat patients suffering from Type 2 diabetes.

Recent progress in pancreatic islet cell therapy

Human pluripotent stem cells (PSCs), including human embryonic stem cells and induced pluripotent stem cells, are promising cell sources in regenerating pancreatic islets through in vitro directed differentiation. Recent progress in this research field has made it possible to generate glucose-responsive pancreatic islet cells from PSCs. Single-cell RNA sequencing techniques have been applied to analyze PSC-derived endocrine beta-cells, which are then compared with human islets. This has led to the identification of novel signaling pathways and molecules involved in lineage commitment during pancreatic differentiation and maturation processes. Single-cell transcriptomics are also used to construct a detailed map of in vivo endocrine differentiation of developing mouse embryos to study pancreatic islet development. Mimicking those occurring in vivo, it was reported that differentiating PSCs can generate similar islet cell structures, while metabolomics analysis highlighted key components involved in PSC-derived pancreatic islet cell function, providing information for the improvement of in vitro pancreatic maturation procedures. In addition, cell transplantation into diabetic animal models, together with the cell delivery system, is studied to ensure the therapeutic potentials of PSC-derived pancreatic islet cells. Combined with gene-editing technology, the engineered mutation-corrected PSC lines originated from diabetes patients could be differentiated into functional pancreatic islet cells, suggesting possible autologous cell therapy in the future. These PSC-derived pancreatic islet cells are a potential tool for studies of disease modeling and drug testing. Herein, we outlined the directed differentiation procedures of PSC-derived pancreatic islet cells, novel findings through transcriptome and metabolome studies, and recent progress in disease modeling.

Differentiation of canine adipose mesenchymal stem cells into insulin-producing cells: comparison of different culture medium compositions

The aim of this study was to differentiate canine adipose-derived mesenchymal stem cells (ADMSCs) into insulin-producing cells by using culture media with different compositions to determine the most efficient media. Stem cells isolated from the fat tissues close to the bitch uterus were distributed into 6 groups: (1) Dulbecco's modified Eagle medium (DMEM)-high glucose (HG), β-mercaptoethanol, and nicotinamide; (2) DMEM-HG, β-mercaptoethanol, nicotinamide, and exendin-4; (3) DMEM-HG, β-mercaptoethanol, nicotinamide, exendin-4, B27, nonessential amino acids, and l-glutamine; (4) DMEM-HG, β-mercaptoethanol, and nicotinamide (for the initial 8-d period), and DMEM-HG, β-mercaptoethanol, nicotinamide, exendin-4, B27, nonessential amino acids, l-glutamine, and basic fibroblast growth factor (for the remaining 8-d period); (5) DMEM-HG and fetal bovine serum; and (6) DMEM-low glucose and fetal bovine serum (standard control group). Adipose-derived mesenchymal stem cells from groups 1 to 5 gradually became round in shape and gathered in clusters. These changes differed between the groups. In group 3, the cell clusters were apparently more in numbers and gathered as bigger aggregates. Dithizone staining showed that groups 3 and 4 were similar in terms of the mean area of each aggregate stained for insulin. However, only in group 4, the number of insulin aggregates and the total area of aggregates stained were significantly bigger than in the other groups. The mRNA expression of PDX1, BETA2, MafA, and Insulin were also confirmed in all the groups. We conclude that by manipulating the composition of the culture medium it is possible to induce canine ADMSCs into insulin-producing cells, and the 2-staged protocol that was used promoted the best differentiation.

Transdifferentiation of both intra- and extra-islet cells into beta cells in nicotinamide treated neonatal diabetic rats: An in situ hybridization and double immunohistochemical study

We aimed to study the effect of nicotinamide (NA) on beta (β)-cell regeneration and apoptosis in streptozotocin induced neonatal rats (n-STZ). Three groups were performed: Control group, n2-STZ group (100 mg/kg STZ on the second day-after birth), n2-STZ + NA group (STZ;100 mg/kg + NA;500 mg/kg/day for 5 days). The pancreatic tissue sections were immunostained with insulin, glucagon, somatostatin, Pdx1, Notch1 and active caspase-3 antibodies, and double immunostained with insulin/PCNA, insulin/glucagon and insulin/somatostatin antibodies. In situ hybridization carried out with insulin probe. Apoptotic β-cell were shown by TUNEL assay, followed by immunostaining. The number of insulin/PCNA, insulin/glucagon and insulin/somatostatin double-positive cells significantly increased in n2-STZ + NA group compared with the other groups (p < 0.001). n2- STZ group had lower number of insulin and Pdx1 positive cells in islets, compared to NA treated diabetics. The insulin and Pdx1 immun positive cells were located in the small clusters or scattered through the exocrine tissue and around to ducts in n2-STZ + NA group. Notch1 positive cell numbers were increased, whereas caspase-3 and TUNEL positive β-cell numbers were decreased in n2-STZ + NA group. NA treatment induces the neogenic insulin positive islets orginated from the differentiation of ductal progenitor cells, transdifferentiation of acinar cells into β cells, and transformation of potent precursor cells and centroacinar cells via the activated Notch expression into β-cells in n-STZ rats.

Functional β-Cell Differentiation of Small-Tail Han Sheep Pancreatic Mesenchymal Stem Cells and the Therapeutic Potential in Type 1 Diabetic Mice

OBJECTIVES

This study aims to investigate the characteristics of sheep pancreatic mesenchymal stem cells (PSCs) and therapeutic potential of differentiated β-like cells in streptozotocin-induced diabetic mice.

METHODS

Pancreatic mesenchymal stem cells were isolated from 3- to 4-month-old sheep embryos, and their biological characteristics were explored. The function and therapeutic potential of differentiated β-like insulin-producing cells were also investigated in vitro and in vivo. Differentiated cells were identified through dithizone staining and immunofluorescence staining. Insulin secretion was analyzed using an enzyme-linked immunosorbent assay kit. The preliminary therapeutic potential of induced β-like cells in diabetic mice was detected by blood glucose and body weight.

RESULTS

Primary PSCs were isolated and subcultured up to passage 36. Immunofluorescence staining presented PSC-expressed important markers such as Pdx1, Nkx6-1, Ngn3, and Nestin. Primary PSCs could be induced into functional pancreatic β-like islet cells with a 3-step protocol. The induced β-like islet cells could ameliorate blood glucose in diabetic mice.

CONCLUSIONS

The method proposed for generating pancreatic islet β cells provided a preliminary phenotypic investigation of induced cell treatment in diabetic mice, and also laid a foundation in the identification of pharmaceutical targets to treat insulin-dependent diabetes.

Chorionic and amniotic placental membrane-derived stem cells, from gestational diabetic women, have distinct insulin secreting cell differentiation capacities

Women with gestational diabetes mellitus (GDM), and their offspring, are at high risk of developing type 2 diabetes. Chorionic (CMSCs) and amniotic mesenchymal stem cells (AMSCs) derived from placental membranes provide a source of autologous stem cells for potential diabetes therapy. We established an approach for the CMSC/AMSC-based generation of functional insulin-producing cells (IPCs). CMSCs/AMSCs displayed significantly elevated levels of NANOG and OCT4 versus bone marrow-derived MSCs, indicating a potentially broad differentiation capacity. Exposure of Healthy- and GDM-CMSCs/AMSCs to long-term high-glucose culture resulted in significant declines in viability accompanied by elevation, markedly so in GDM-CMSCs/AMSCs, of senescence/stress markers. Short-term high-glucose culture promoted pancreatic transcription factor expression when coupled to a 16-day step-wise differentiation protocol; activin A, retinoic acid, epidermal growth factor, glucagon-like peptide-1 and other chemical components, generated functional IPCs from both Healthy- and GDM-CMSCs. Healthy-/GDM-AMSCs displayed betacellulin-sensitive insulin expression, which was not secreted upon glucose challenge. The pathophysiological state accompanying GDM may cause irreversible impairment to endogenous AMSCs; however, GDM-CMSCs possess comparable therapeutic potential with Healthy-CMSCs and can be effectively reprogrammed into insulin-secreting cells.

In vitro differentiation of single donor derived human dental mesenchymal stem cells into pancreatic β cell-like cells

The present study was carried out to investigate and compare the in vitro differentiation potential of mesenchymal stem cells (MSCs) isolated from human dental tissues (pulp, papilla, and follicle) of the same donor. MSCs were isolated from dental tissues (pulp, papilla, and follicle) following digestion method and were analyzed for the expression of pluripotent markers and cell surface markers. All three types of MSCs were evaluated for their potential to differentiate into mesenchymal lineages. Further, the MSCs were differentiated into pancreatic β cell-like cells using multistep protocol and characterized for the expression of pancreatic lineage specific markers. Functional properties of differentiated pancreatic β cell-like cells were assessed by dithizone staining and glucose challenge test. All three types of MSCs showed fibroblast-like morphology upon culture and expressed pluripotent, and mesenchymal cell surface markers. These MSCs were successfully differentiated into mesenchymal lineages and transdifferentiated into pancreatic β cell-like cells. Among them, dental follicle derived MSCs exhibits higher transdifferentiation potency toward pancreatic lineage as evaluated by the expression of pancreatic lineage specific markers both at mRNA and protein level, and secreted higher insulin upon glucose challenge. Additionally, follicle-derived MSCs showed higher dithizone staining upon differentiation. All three types of MSCs from a single donor possess similar cellular properties and can differentiate into pancreatic lineage. However, dental follicle derived MSCs showed higher potency toward pancreatic lineage than pulp and papilla derived MSCs, suggesting their potential application in future stem cell based therapy for the treatment of diabetes.

Human beta cells generated from pluripotent stem cells or cellular reprogramming for curing diabetes

Diabetes is a group of metabolic diseases characterized by aberrantly high blood glucose levels caused by defects in insulin secretion, its action, or both, which affects approximately 30.3 million people (9.4% of the population) in the United States. This review will focus on using human β cells to treat and cure diabetes because β cells are absent, due to an autoimmune destruction, in Type 1 diabetes or dysfunctional in Type 2 diabetes. In order to generate enough functional β cells for diabetes treatment (0.1 to 1 billion cells to treat one patient), a basic science approach by mimicking what happens in normal pancreatic development must be closely aligned with engineering. Two general approaches are discussed here. The first one uses human pluripotent stem cells (hPSCs) to perform directed differentiation of hPSCs to β cells. This is advantageous because hPSCs grow indefinitely, providing a virtually unlimited source of material. Therefore, if we develop an efficient β cell differentiation protocol, we can essentially generate an unlimited amount of β cells for disease modeling and diabetes treatment. The second approach is cellular reprogramming, with which we may begin with any cell type and covert it directly into a β cell. The success of this cellular reprogramming approach, however, depends on the discovery of a robust and efficient transcription factor cocktail that can ignite this process, similar to what has been achieved in generating induced pluripotent stem cells. This discovery should be possible through identifying the important transcription factors and pioneer factors via recent advances in single-cell RNA sequencing. In short, a new renaissance in pancreas developmental biology, stem cell engineering, and cellular reprogramming for curing diabetes appears to be on the horizon.

Enhanced survival and insulin secretion of insulinoma cell aggregates by incorporating gelatin hydrogel microspheres

Introduction

The objective of this study is to evaluate the survival and glucose-induced insulin secretion of rat-derived insulinoma cells (INS-1) from their aggregates incorporating different size of gelatin hydrogel microspheres comparing with microspheres-free cell aggregates.

Methods

The gelatin hydrogel microspheres were prepared by the conventional w/o emulsion method. The INS-1 cells were cultured in a V-bottomed well, combining with or without the gelatin hydrogel microspheres to form their aggregates with or without microspheres.

Results

When the cell viability, the live cell number, the reductase activity, and the insulin secretion of cell aggregates were evaluated 7 or 14 days after incubation, the cell aggregates incorporating gelatin hydrogel microspheres showed higher cell viability, reductase activity and a larger number of live cells. The cell aggregates incorporating larger size and number of gelatin hydrogel microspheres secreted a larger amount of insulin, compared with those incorporating smaller size and number of microspheres or without microspheres.

Conclusion

It is conceivable that the incorporation of gelatin hydrogel microspheres in cell aggregates is promising to improve their survival and insulin secretion function.

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INS-1 cell aggregates incorporating gelatin hydrogel microspheres are prepared.

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Gelatin hydrogel microspheres incorporation improves cell viability and glucose-induced insulin secretion of cell aggregates.

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The size and number of gelatin hydrogel microspheres affected the cell condition and function.

An arduous journey from human pluripotent stem cells to functional pancreatic β cells

Type 1 and type 2 diabetes are caused by a destruction and decrease in the number of functional insulin-producing β cells, respectively; therefore, the generation of functional β cells from human embryonic stem cells and human induced pluripotent stem cells, collectively known as human pluripotent stem cells (hPSCs), for potential cell replacement therapy and disease modelling is an intensely investigated area. Recent scientific breakthroughs enabled derivation of large quantities of human pancreatic β-like cells in vitro, although with varied glucose-stimulated insulin secretion kinetics. In the present review, we comprehensively summarize, compare and critically analyze the intricacies of these developing technologies, including differentiation platforms, robustness of protocols, and methodologies used to characterize hPSC-derived β-like cells. We also discuss experimental issues that need to be resolved before these β-like cells can be used clinically.

A study of DNA damage in buccal cells of consumers of well- and/or tap-water using the comet assay: Assessment of occupational exposure to genotoxicants

Because of concerns that natural aquifers in the region of Todos Santos (Baja California Sur, Mexico) might be contaminated by organochlorine pesticides and heavy metals, a case-control study was conducted among consumers and non-consumers of well- and/or tap-water to determine risks to human health. This study was based on a genotoxic evaluation of buccal cells using the Comet assay technique. Levels of DNA damage in the consumers group were significantly higher than those of the control group. However, occupational exposure to genotoxicants showed to be the critical factor rather than water consumption. Taking into account the professions of well- and/or tap-water consumers, agricultural workers exposed directly (those who fumigated) or indirectly (those not involved in fumigating) to agrochemicals showed greater genetic damage than controls. This difference persisted even when age, and whether the person smoked or consumed alcoholic drinks were considered. These factors were not associated with the level of genetic damage observed. Chemical analyses of organochlorine pesticides and heavy metals were carried out to evaluate the water quality of wells, faucets, and surface water of canals consumed by the population and/or used for irrigation. High concentrations of α and β endosulfan were detected in water of surface canals. Although our inventory of agrochemicals employed in the region showed the use of products considered carcinogenic and/or mutagenic, they were not detected by the analytical techniques used. Heavy metals (arsenic, mercury, and lead) were detected in water of some wells used for irrigation and human consumption. Environ. Mol. Mutagen. 58:619-627, 2017. © 2017 Wiley Periodicals, Inc.

Molecular Cloning of the Porcine Insulin cDNA Using a Monolayer Culture of Pancreatic Endocrine Cells

Porcine pancreatic endocrine cells are an attractive candidate for islet cell transplantation in view of the immunological properties and structural similarities of porcine insulin to human insulin. We recently established a method of isolation and a primary monolayer culture of porcine pancreatic endocrine cells. In this study, cloning of the porcine insulin cDNA was performed to clarify the genetic background of the purified isolated cells. A homology-based PCR cloning method was employed to determine the sequence using mRNA extracted from the monolayer-forming cells, and the candidate products were then determined by a homology search on the human insulin cDNA. According to the newly identified sequence, rapid amplification of cDNA ends was applied to the 5′ and 3′ ends, and the entire cDNA sequence was determined. Gene and protein expression was confirmed by Northern blotting, immunohistochemistry, and enzyme assay. To examine the transcriptional level, the cultured cells were incubated in a 20 mM D-glucose medium in the presence or absence of 5 μM forskolin. The porcine insulin cDNA exhibited a high homology to the human cDNA and showed 85% matching with the human amino acid sequence. D-Glucose at 20 mM stimulated the insulin secretion and mRNA expression, and further addition of 5 μM forskolin with the glucose was applied as the strongest stimulus in this culture system.

Development of Fetal Sheep Pancreas after Transplantation into Athymic Mice

The capacity of the fetal sheep pancreas to grow and function when transplanted into athymic mice was examined to determine whether this source of tissue might be of potential use in reversing diabetes. For this purpose fetal sheep pancreases were obtained in the period between 50 days of gestation and fullterm (148 days). Explants (1 mm3) in organ culture secreted insulin for at least 7 days, but in steadily diminishing amounts. Acute exposure to arginine (10 mM) and theophylline (10 mM), but not glucose (20 mM), calcium chloride (10 mM), and sodium butyrate (10 mM), caused acute secretion of insulin. Explants survived for many months when grafted beneath the renal capsule of athymic mice, but their growth was less, the epithelial-like component smaller, and the percentage of endocrine cells (31 ± 5%) fewer than the case of transplanted fetal human pancreas. The β cell was the predominant endocrine cell in the ungrafted fetal sheep pancreas. In the transplanted fetal sheep pancreas this was not so, the α and PP cells being dominant—β:α:S:PP = 3:14:3:11. This pattern was unchanged when the recipient mice were hyperglycemic—β:α:δ:PP = 4:13:4:28, with no reduction of blood glucose levels being observed for up to 4 mo after transplantation. Altering the site of transplantation to the spleen or liver did not improve survival of the endocrine cells. Fetal sheep pancreatic explants when transplanted into athymic rats failed to survive. Thus, although the unusual pattern of endocrine differentiation in fetal sheep pancreas transplanted into athymic mice makes it an interesting model for further studies of fetal development, it is not of benefit in normalizing the blood glucose levels of the recipients.

Isolation and Characterization of a Cell Line from the Epithelial Cells of the Human Fetal Pancreas

Pancreatic cell lines are useful for basic studies of pancreatic biology and for possible application to cell transplantation therapies for diabetes. A retroviral vector expressing simian virus 40 (SV40) T antigen and H-rasval12 was used to infect a monolayer culture of epithelial cells from an 18-wk human fetal pancreas. Infected cells gave rise to a clonal epithelial cell line, designated TRM-1. This cell line expresses epithelial markers as well as glut2 and small amounts of insulin and glucagon. TRM-1 is the first cell line to be generated from the human fetal pancreas and also the first cell line derived directly from the fetal pancreas of any species. The approach that we have used to develop TRM-1 should be applicable to isolating cell lines from other stages of human pancreatic development. Copyright © 1997 Elsevier Science, Inc.

Production and Characterization of Fetal Sheep Pancreatic Islet-Like Cell Clusters

Explants of fetal sheep pancreas transplanted into diabetic athymic mice survive for many months but there is only partial differentiation of the endocrine cells. As an alternative form of graft we examined the possibility of creating islet-like cell clusters (ICCs) by collagenase digestion of the fetal sheep pancreas, as has been described for human and porcine fetal pancreas. Such ICCs did form at the rate of 6-23 per 10 mg pancreas; their size varied between 65 and 474 μm (median 232 μm) and their insulin content was 1.6 ± 0.2 mU per 20 ICCs. Laser scanning confocal analysis showed that 4.6 ± 0.7% of the cells contained insulin. Insulin was secreted from ICCs maintained in culture at the daily rate of 2.5 mU per 30 ICCs. Arginine but not glucose or theophylline enhanced acute insulin secretion in vitro. Transplantation of up to 1000 ICCs into athymic and scid mice resulted in sparse growth of the epithelial-like cells in the graft and only partial differentiation of the endocrine cells. Hyperglycaemia in diabetic recipients was not normalized. Thus, while functioning ICCs can be created from fetal sheep pancreas, they do not appear to be appropriate for transplantation to reverse diabetes in mice.

Protection of Mouse Islet Isografts from Nonspecific Inflammatory Damage by Recipient Treatment with Nicotinamide and 15-Deoxyspergualin

The major cause of primary nonfunction of transplanted islets is nonspecific inflammation associated with the transplantation procedures. Using mouse islet isografts, we attempted to prevent graft loss mediated by nonspecific inflammation using recipient treatment with nicotinamide (NA) and 15-deoxyspergualin (DSG). Newborn BALB/c islets, ranging in numbers between 1200 and 1500, were transplanted into syngeneic adult mice made diabetic by intravenous injection of 200 mg/kg streptozotocin. Recipient mice were divided into the following four groups, based on the treatment protocol of NA and DSG: intraperitoneal injection (IP) of normal saline (Group 1), IP injection of 2500 mg/kg NA (Group 2), IP injection of 5 mg/kg DSG (Group 3), and IP injection of NA + DSG (Group 4). Treatment started Day -1 and continued until Day 9 (Day 0 is day of transplantation). Blood and urine glucose, body weight, and intravenous glucose tolerance tests (IV-GTT) were examined after transplantation. Reversal of diabetes, as indicated by normoglycemia and negative urine glucose, was higher in Groups 2 (75%), 3 (50%), and 4 (85.7%), compared to Group 1 (11.1%). Especially in Group 4, the endocrine function and morphology of grafted islets were well preserved as shown by K values of IV-GTT and histological studies. These results suggest the importance of islet protection from irreversible damage by nonspecific inflammation at earlier stages of implantation, and the effectiveness of a short course of treatment with NA and DSG.

Sonic hedgehog pathway suppression and reactivation accelerates differentiation of rat adipose-derived mesenchymal stromal cells toward insulin-producing cells

BACKGROUND AIMS

Sonic hedgehog (Shh) is an intercellular signaling molecule that regulates pancreas development in mammals. Manipulation of Shh signaling pathway can be used as reliable approach to improve the generation of functional insulin-producing cells (IPCs) from mesenchymal stromal cells (MSCs).

METHODS

In the present study, a novel differentiation protocol was used to produce IPCs from adipose tissue-derived MSCs (ATDMSCs) based on sequential inhibition and reactivation of Shh pathway. ATDMSCs were differentiated into IPCs via a 14-day basic protocol using 1% insulin transferrin selenium (ITS) and 1% nicotinamide in Dulbecco's Modified Eagle's Medium medium. A mixture of 0.25 µmol/L cyclopamine + 64 ng/mL basic fibroblast growth factor at day 3 of differentiation and 150 ng/mL recombinant Shh at day 11 of differentiation were used, respectively, to promote sequential inhibition and reactivation of Shh pathway. Insulin granule formation, glucose-stimulated insulin secretion and gene expression pattern related to the pancreatic endocrine development and function were analyzed in manipulated and unmanipulated IPCs.

RESULTS

IPCs obtained after Shh manipulation secreted higher amounts of insulin in vitro. This phenotype was accompanied by increased expression of both genes critical for β-cell function and transcription factors associated with their mature phenotype including Pdx1, MafA, Nkx2.2, Nkx6.1, Ngn3, Isl1 and insulin at day 14 of differentiation.

CONCLUSIONS

Our findings indicated that the early inhibition and late reactivation of Shh signaling pathway during the differentiation of ATDMSCs improved the functional properties of IPCs, a novel method that could be considered as an alternative approach for cell-based therapy for type 1 diabetes.

Combinations of Activin A or Nicotinamide with the Pancreatic Transcription Factor PDX1 Support Differentiation of Human Amnion Epithelial Cells Toward a Pancreatic Lineage

The differentiation of multipotent stem cells toward a pancreatic lineage provides us with an alternative cell-based therapeutic approach to type 1 diabetes and enables us to study pancreas development. The current study aims to study the effect of growth factors such as activin A or nicotinamide, alone and in combinations with the transcription factor, PDX1 (pancreatic and duodenal homeobox-1), on human amnion epithelial cells (hAECs) toward a pancreatic lineage. Ectopic expression of Pdx1 followed by treatment of hAECs with nicotinamide for 4 days resulted in strong induction of pancreatic endoderm and pancreatic progenitor genes, including NKX6.1 and NEUROD1. Pancreatic lineage cells expressing PDX1, SOX17, and RFX6 are derived from Pdx1-transduced hAECs treated with activin A or nicotinamide, but not cells treated with activin A or nicotinamide alone. Our study provides a novel culture protocol for generating pancreas-committed cells from hAECs and reveals an interplay between Pdx1 and activin A/nicotinamide signaling in early pancreatic fate determination.

Mesenchymal stem cells and differentiated insulin producing cells are new horizons for pancreatic regeneration in type I diabetes mellitus

BACKGROUND

Diabetes mellitus has become the third human killer following cancer and cardiovascular disease. Millions of patients, often children, suffer from type 1 diabetes (T1D). Stem cells created hopes to regenerate damaged body tissues and restore their function.

AIM

This work aimed at clarifying and comparing the therapeutic potential of differentiated and non-differentiated mesenchymal stem cells (MSCs) as a new line of therapy for T1D.

METHODS

40 Female albino rats divided into group I (control): 10 rats and group II (diabetic), III and IV, 10 rats in each, were injected with streptozotocin (50mg/kg body weight). Group III (MSCs) were transplanted with bone marrow derived MSCs from male rats and group IV (IPCs) with differentiated insulin producing cells. Blood and pancreatic tissue samples were taken from all rats for biochemical and histological studies.

RESULTS

MSCs reduced hyperglycemia in diabetic rats on day 15 while IPCs normalizes blood glucose level on day 7. Histological and morphometric analysis of pancreas of experimental diabetic rats showed improvement in MSCs-treated group but in IPCs-treated group, β-cells insulin immunoreactions were obviously returned to normal, with normal distribution of β-cells in the center and other cells at the periphery. Meanwhile, most of the pathological lesions were still detected in diabetic rats.

CONCLUSION

MSCs transplantation can reduce blood glucose level in recipient diabetic rats. IPCs initiate endogenous pancreatic regeneration by neogenesis of islets. IPCs are better than MSCs in regeneration of β-cells. So, IPCs therapy can be considered clinically to offer a hope for patients suffering from T1D.

Demethylation of induced pluripotent stem cells from type 1 diabetic patients enhances differentiation into functional pancreatic β cells

Type 1 diabetes (T1D) can be managed by transplanting either the whole pancreas or isolated pancreatic islets. However, cadaveric pancreas is scarcely available for clinical use, limiting this approach. As such, there is a great need to identify alternative sources of clinically usable pancreatic tissues. Here, we used induced pluripotent stem (iPS) cells derived from patients with T1D to generate glucose-responsive, insulin-producing cells (IPCs) via 3D culture. Initially, T1D iPS cells were resistant to differentiation, but transient demethylation treatment significantly enhanced IPC yield. The cells responded to high-glucose stimulation by secreting insulin in vitro The shape, size, and number of their granules, as observed by transmission electron microscopy, were identical to those found in cadaveric β cells. When the IPCs were transplanted into immunodeficient mice that had developed streptozotocin-induced diabetes, they promoted a dramatic decrease in hyperglycemia, causing the mice to become normoglycemic within 28 days. None of the mice died or developed teratomas. Because the cells are derived from "self," immunosuppression is not required, providing a much safer and reliable treatment option for T1D patients. Moreover, these cells can be used for drug screening, thereby accelerating drug discovery. In conclusion, our approach eliminates the need for cadaveric pancreatic tissue.

Chitosan-assisted differentiation of porcine adipose tissue-derived stem cells into glucose-responsive insulin-secreting clusters

The unique advantage of easy access and abundance make the adipose-derived stem cells (ADSCs) a promising system of multipotent cells for transplantation and regenerative medicine. Among the available sources, porcine ADSCs (pADSCs) deserve especial attention due to the close resemblance of human and porcine physiology, as well as for the upcoming availability of humanized porcine models. Here, we report on the isolation and conversion of pADSCs into glucose-responsive insulin-secreting cells. We used the stromal-vascular fraction of the dorsal subcutaneous adipose from 9-day-old male piglets to isolate pADSCs, and subjected the cells to an induction scheme for differentiation on chitosan-coated plates. This one-step procedure promoted differentiation of pADSCs into pancreatic islet-like clusters (PILC) that are characterized by the expression of a repertoire of pancreatic proteins, including pancreatic and duodenal homeobox (Pdx-1), insulin gene enhancer protein (ISL-1) and insulin. Upon glucose challenge, these PILC secreted high amounts of insulin in a dose-dependent manner. Our data also suggest that chitosan plays roles not only to enhance the differentiation potential of pADSCs, but also to increase the glucose responsiveness of PILCs. Our novel approach is, therefore, of great potential for transplantation-based amelioration of type 1 diabetes.

Enhanced differentiation of human amniotic fluid-derived stem cells into insulin-producing cells in vitro

AIMS/INTRODUCTION

To investigate the ability of human amniotic fluid stem cells (hAFSCs) to differentiate into insulin-producing cells.

MATERIALS AND METHODS

hAFSCs were induced to differentiate into pancreatic cells by a multistep protocol. The expressions of pancreas-related genes and proteins, including pancreatic and duodenal homeobox-1, insulin, and glucose transporter 2, were detected by polymerase chain reaction and immunofluorescence. Insulin secreted from differentiated cells was tested by enzyme-linked immunosorbent assay.

RESULTS

hAFSCs were successfully isolated from amniotic fluid that expressed the pluripotent markers of embryonic stem cells, such as Oct3/4, and mesenchymal stem cells, such as integrin β-1 and ecto-5'-nucleotidase. Here, we first obtained the hAFSCs that expressed pluripotent marker stage-specific embryonic antigen 1. Real-time polymerase chain reaction analysis showed that pancreatic and duodenal homeobox-1, paired box gene 4 and paired box gene 6 were expressed in the early phase of induction, and then stably expressed in the differentiated cells. The pancreas-related genes, such as insulin, glucokinase, glucose transporter 2 and Nkx6.1, were expressed in the differentiated cells. Immunofluorescence showed that these differentiated cells co-expressed insulin, C-peptide, and pancreatic and duodenal homeobox-1. Insulin was released in response to glucose stimulation in a manner similar to that of adult human islets.

CONCLUSIONS

The present study showed that hAFSCs, under selective culture conditions, could differentiate into islet-like insulin-producing cells, which might be used as a potential source for transplantation in patients with type 1 diabetes mellitus.

Mechanisms of adult human β-cell in vitro dedifferentiation and redifferentiation

Recent studies in animal models and human pathological specimens suggest the involvement of β-cell dedifferentiation in β-cell dysfunction associated with type 2 diabetes. Dedifferentiated β-cells may be exploited for endogenous renewal of the β-cell mass. However, studying human β-cell dedifferentiation in diabetes presents major difficulties. We have analysed mechanisms involved in human β-cell dedifferentiation in vitro, under conditions that allow cell proliferation. Although there are important differences between the two cellular environments, β-cell dedifferentiation in the two conditions is likely to share a number of common pathways. Insights from the in vitro studies may lead to development of approaches for redifferentiation of endogenous dedifferentiated β-cells.

In vitro differentiation potential of human haematopoietic CD34(+) cells towards pancreatic β-cells

Haematopoietic stem cells (HSCs) possess multipotent ability to differentiate into various types of cells on providing appropriate niche. In the present study, the differentiating potential of human HSCs into β-cells of islets of langerhans was explored. Human HSCs were apheretically isolated from a donor and cultured. Phenotypic characterization of CD34 glycoprotein in the growing monolayer HSCs was confirmed by immunocytochemistry and flow cytometry techniques. HSCs were induced by selection with beta cell differentiating medium (BDM), which consists of epidermal growth factor (EGF), fibroblast growth factor (FGF), transferrin, Triiodo-l-Tyronine, nicotinamide and activin A. Distinct morphological changes of differentiated cells were observed on staining with dithizone (DTZ) and expression of PDX1, insulin and synaptophysin was confirmed by immunocytochemistry. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed distinct expression of specific β-cell markers, pancreatic and duodenal homeobox-1 (PDX1), glucose transporter-2 (GLUT-2), synaptophysin (SYP) and insulin (INS) in these differentiated cells compared to HSCs. Further, these cells exhibited elevated expression of INS gene at 10 mM glucose upon inducing with different glucose concentrations. The prominent feature of the obtained β-cells was the presence of glucose sensors, which was determined by glucokinase activity and high glucokinase activity compared with CD34(+) stem cells. These findings illustrate the differentiation of CD34(+) HSCs into β-cells of islets of langerhans.

Insulin-Producing Endocrine Cells Differentiated In Vitro From Human Embryonic Stem Cells Function in Macroencapsulation Devices In Vivo

The PEC-01 cell population, differentiated from human embryonic stem cells (hESCs), contains pancreatic progenitors (PPs) that, when loaded into macroencapsulation devices (to produce the VC-01 candidate product) and transplanted into mice, can mature into glucose-responsive insulin-secreting cells and other pancreatic endocrine cells involved in glucose metabolism. We modified the protocol for making PEC-01 cells such that 73%-80% of the cell population consisted of PDX1-positive (PDX1+) and NKX6.1+ PPs. The PPs were further differentiated to islet-like cells (ICs) that reproducibly contained 73%-89% endocrine cells, of which approximately 40%-50% expressed insulin. A large fraction of these insulin-positive cells were single hormone-positive and expressed the transcription factors PDX1 and NKX6.1. To preclude a significant contribution of progenitors to the in vivo function of ICs, we used a simple enrichment process to remove remaining PPs, yielding aggregates that contained 93%-98% endocrine cells and 1%-3% progenitors. Enriched ICs, when encapsulated and implanted into mice, functioned similarly to the VC-01 candidate product, demonstrating conclusively that in vitro-produced hESC-derived insulin-producing cells can mature and function in vivo in devices. A scaled version of our suspension culture was used, and the endocrine aggregates could be cryopreserved and retain functionality. Although ICs expressed multiple important β cell genes, the cells contained relatively low levels of several maturity-associated markers. Correlating with this, the time to function of ICs was similar to PEC-01 cells, indicating that ICs required cell-autonomous maturation after delivery in vivo, which would occur concurrently with graft integration into the host.

SIGNIFICANCE

Type 1 diabetes (T1D) affects approximately 1.25 million people in the U.S. alone and is deadly if not managed with insulin injections. This paper describes the production of insulin-producing cells in vitro and a new protocol for producing the cells, representing another potential cell source for a diabetes cell therapy. These cells can be loaded into a protective device that is implanted under the skin. The device is designed to protect the cells from immune rejection by the implant recipient. The implant can engraft and respond to glucose by secreting insulin, thus potentially replacing the β cells lost in patients with T1D.

In vitro differentiation of human amniotic epithelial cells into insulin-producing 3D spheroids

Regenerative medicine and stem cell therapy may represent the solution for the treatment of non-curable human diseases such as type 1 diabetes. In this context of growing demand for functional and safe stem cells, human amniotic epithelial cells (hAECs) from term placenta have attracted increasing interest for their wide availability, stem cell properties, and differentiation plasticity, which make them a promising tool for stem cell-based therapeutic applications. We initially assayed the stemness characteristics of hAECs in serum-free conditions. Subsequently we developed a culture procedure on extracellular matrix for the formation of three-dimensional (3D) spheroids. Finally, we tested the immunomodulation and differentiation potential of hAEC spheroids: the presence of pancreatic endocrine hormones was revealed with transmission electron microscopy and immunofluorescence analyses; the release of C-peptide in hyperglycemic conditions was assayed with ELISA. The serum-free culture conditions we applied proved to maintain the basic stemness characteristics of hAECs. We also demonstrated that 3D spheroids formed by hAECs in extracellular matrix can be induced to differentiate into insulin-producing cells. Finally, we proved that control and induced cells equally inhibit the proliferation of activated mononuclear cells. The results of this study highlight the properties of amnion derived epithelial cells as promising and abundant source for cell-based therapies. In particular we are the first group to show the in vitro pancreatic induction of hAECs cultured on extracellular matrix in a 3D fashion. We accordingly propose the outcomes of this study as a novel contribution to the development of future cell replacement therapies involving placenta-derived cells.

Transplantation of differentiated umbilical cord mesenchymal cells under kidney capsule for control of type I diabetes in rat

Nowadays, stem cells have been introduced as an appropriate source of regenerative medicine for treatment of type I diabetes. Human umbilical cord matrix-derived mesenchymal cells (hUCMC) have successfully been differentiated into insulin producing cells. The isolated hUCM cells were characterized by the expression of stem cell surface markers and by differentiation into adipocytes and osteocytes. The hUCMCs were cultured with different concentrations of neural conditional medium (NCM) and were induced to differentiate into insulin producing cells (IPCs). As 60% NCM concentration resulted in higher nestin and PDX1 expression, the cells were first exposed to 60% NCM and were then induced for IPCs differentiation. PDX1 and insulin gene expression was evaluated in the treated cells. Also, the secretion capacity of the IPCs was assessed by glucose challenge test. IPCs were transferred under the rat kidney capsule. Blood glucose level, weight gain and immunohistochemistry assessments were done in the treated animals. hUCMC expressed mesenchymal cell surface markers and successfully differentiated into adipocytes and osteocytes. Higher NCM concentration resulted in higher PDX1 and nestin expression. The IPCs expressed insulin and PDX1. IPCs were detectable under the kidney capsule 2 months after injection. IPCs transplantation resulted in a sharp decline of blood sugar level and less weight loss. Differentiated hUCM cells could alleviate the insulin deprivation in the rat model of type I diabetes. In addition, higher NCM concentration leads to more differentiation into IPCs and more nestin and PDX1 expression. Kidney capsule can serve as a suitable nominee for IPCs transplantation.

Efficient generation of NKX6-1+ pancreatic progenitors from multiple human pluripotent stem cell lines

Human pluripotent stem cells (hPSCs) represent a renewable source of pancreatic beta cells for both basic research and therapeutic applications. Given this outstanding potential, significant efforts have been made to identify the signaling pathways that regulate pancreatic development in hPSC differentiation cultures. In this study, we demonstrate that the combination of epidermal growth factor (EGF) and nicotinamide signaling induces the generation of NKX6-1⁺ progenitors from all hPSC lines tested. Furthermore, we show that the size of the NKX6-1⁺ population is regulated by the duration of treatment with retinoic acid, fibroblast growth factor 10 (FGF10), and inhibitors of bone morphogenetic protein (BMP) and hedgehog signaling pathways. When transplanted into NOD scid gamma (NSG) recipients, these progenitors differentiate to give rise to exocrine and endocrine cells, including monohormonal insulin⁺ cells. Together, these findings provide an efficient and reproducible strategy for generating highly enriched populations of hPSC-derived beta cell progenitors for studies aimed at further characterizing their developmental potential in vivo and deciphering the pathways that regulate their maturation in vitro.

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EGF and nicotinamide induce NKX6-1⁺ progenitors from hPSC-derived endoderm

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NKX6-1⁺ progenitor generation can be controlled by the duration of stage 3 treatment

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The generation of polyhormonal cells is dependent on hedgehog signaling inhibition

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NKX6-1⁺ progenitors give rise to ductal, acinar, and endocrine cells in vivo

Generation of insulin-producing cells from C3H10T1/2 mesenchymal progenitor cells

Mesenchymal stem cells (MSCs) have been reported to be an attractive source for the generation of transplantable surrogate β cells. A murine embryonic mesenchymal progenitor cell line C3H10T1/2 has been recognized as a model for MSCs, because of its multi-lineage differentiation potential. The purpose of this study was to explore whether C3H/10T1/2 cells have the potential to differentiate into insulin-producing cells (IPCs). Here, we investigated and compared the in vitro differentiation of rat MSCs and C3H10T1/2 cells into IPCs. After the cells underwent IPC differentiation, the expression of differentiation markers were detected by immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time RT-PCR (qRT-PCR) and Western blotting. The insulin secretion was evaluated by enzyme-linked immunosorbent assay (ELISA). Furthermore, these differentiated cells were transplanted into streptozotocin-induced diabetic mice and their biological functions were tested in vivo. This study reports a 2-stage method to generate IPCs from C3H10T1/2 cells. Under specific induction conditions for 7-8 days, C3H10T1/2 cells formed three-dimensional spheroid bodies (SBs) and secreted insulin, while generation of IPCs derived from rat MSCs required a long time (more than 2 weeks). Furthermore, these IPCs derived from C3H10T1/2 cells were injected into diabetic mice and improves basal glucose, body weight and exhibited normal glucose tolerance test. The present study provided a simple and faithful in vitro model for further investigating the mechanism underlying IPC differentiation of MSCs and cell replacement therapy for diabetes.