Spontaneous in vivo differentiation of embryonic stem cell-derived pancreatic endoderm-like cells corrects hyperglycemia in diabetic mice

Are Tanycytes the Missing Link Between Type 2 Diabetes and Alzheimer's Disease?

Tanycytes are highly specialized bipolar ependymal cells that line the ventrolateral wall and the floor of the third ventricle in the brain and form a blood-cerebrospinal fluid barrier at the level of the median eminence. They play a pivotal role in regulating metabolic networks that control body weight and energy homeostasis. Due to the glucosensing function of tanycytes, they could be considered as a critical player in the pathogenesis of type 2 diabetes. Genetic fate mapping studies have established the role of tanycytes for the newly detected adult hypothalamic neurogenesis with important implications for metabolism as well as pathophysiology of various neurodegenerative diseases. We believe that a comprehensive understanding of the physiological mechanisms underlying their neuroplasticity, glucosensing, and cross talk with endothelial cells will enable us to achieve metabolic homeostasis in type 2 diabetes patients and possibly delay the progression of Alzheimer's disease and hopefully improve cognitive function.

Human iPS cell-derived insulin producing cells form vascularized organoids under the kidney capsules of diabetic mice

Type 1 diabetes (T1D) is caused by autoimmune disease that leads to the destruction of pancreatic β-cells. Transplantation of cadaveric pancreatic organs or pancreatic islets can restore normal physiology. However, there is a chronic shortage of cadaveric organs, limiting the treatment of the majority of patients on the pancreas transplantation waiting list. Here, we hypothesized that human iPS cells can be directly differentiated into insulin producing cells (IPCs) capable of secreting insulin. Using a series of pancreatic growth factors, we successfully generated iPS cells derived IPCs. Furthermore, to investigate the capability of these cells to secrete insulin in vivo, the differentiated cells were transplanted under the kidney capsules of diabetic immunodeficient mice. Serum glucose levels gradually declined to either normal or near normal levels over 150 days, suggesting that the IPCs were secreting insulin. In addition, using MRI, a 3D organoid appeared as a white patch on the transplanted kidneys but not on the control kidneys. These organoids showed neo-vascularization and stained positive for insulin and glucagon. All together, these data show that a pancreatic organ can be created in vivo providing evidence that iPS cells might be a novel option for the treatment of T1D.

Tissue engineering

Ultimately much work remains to be done in the companion fields of biomaterials and stem cells. Nonetheless, the monumental progress in TE that has been reported in the studies summarized here demonstrates that regenerative approaches to problems in general surgery need to be explored in more depth. Furthermore, the surgical disciplines of reconstruction and transplantation need to recognize their research counterparts in TE, given its potential to actualize freedom from immunosuppression, one of the most elusive goals in modern surgery. The engineering and proliferation of autologous cells, tissues, and organs ex vivo before surgical operation can significantly reduce the obstacles current practitioners are intimately familiar with: donor site morbidity and immunologic rejection. Therefore, in addition to the truly exciting research and development prospects and implications for the commercial sector, patients with end-stage diseases and debilitating injury stand to gain the most from clinically adapted TE therapies.

Induced pluripotent stem cells without c-Myc reduce airway responsiveness and allergic reaction in sensitized mice

BACKGROUND

Allergic disorders have increased substantially in recent years. Asthma is characterized by airway damage and remodeling. Reprogramming induced pluripotent stem cells (iPSCs) from adult somatic cells transfected by Oct-4/Sox-2/Klf-4, but not c-Myc, has shown the potential of embryonic-like cells. These cells have potential for multilineage differentiation and provide a resource for stem cell-based utility. However, the therapeutic potential of iPSCs without c-Myc (iPSC-w/o-c-Myc) in allergic diseases and airway hyperresponsiveness has not been investigated. The aim of this study was to evaluate the therapeutic effect of iPSC-w/o-c-Myc transplantation in a murine asthma model.

METHODS

BALB/c mice were sensitized with alum-adsorbed ovalbumin (OVA) and then challenged with aerosolized OVA. Phosphate-buffered saline or iPSC-w/o-c-Myc was then intravenously injected after inhalation. Serum allergen-specific antibody levels, airway hyperresponsiveness, cytokine levels in spleen cells and bronchoalveolar lavage fluid (BALF), and cellular distribution in BALF were then examined.

RESULTS

Treatment with iPSC-w/o-c-Myc effectively suppressed both Th1 and Th2 antibody responses, which was characterized by reduction in serum allergen-specific IgE, IgG, IgG1, and IgG2a levels as well as in interleukin-5 and interferon-γ levels in BALF and in OVA-incubated splenocytes. Meanwhile, regulatory cytokine, interleukin-10, was enhanced. Transplantation of iPSC-w/o-c-Myc also significantly attenuated cellular infiltration in BALF and allergic airway hyperresponsiveness. However, no tumor formation was observed 6 months after transplantation.

CONCLUSIONS

Administration of iPSC-w/o-c-Myc not only inhibited Th1 inflammatory responses but also had therapeutic effects on systemic allergic responses and airway hyperresponsiveness. iPSC-w/o-c-Myc transplantation may be a potential modality for treating allergic reactions and bronchial asthma.

Amniotic fluid stem cells prevent β-cell injury

BACKGROUND AIMS

The contribution of amniotic fluid stem cells (AFSC) to tissue protection and regeneration in models of acute and chronic kidney injuries and lung failure has been shown in recent years. In the present study, we used a chemically induced mouse model of type 1 diabetes to determine whether AFSC could play a role in modulating β-cell injury and restoring β-cell function.

METHODS

Streptozotocin-induced diabetic mice were given intracardial injection of AFSC; morphological and physiological parameters and gene expression profile for the insulin pathway were evaluated after cell transplantation.

RESULTS

AFSC injection resulted in protection from β-cell damage and increased β-cell regeneration in a subset of mice as indicated by glucose and insulin levels, increased islet mass and preservation of islet structure. Moreover, β-cell preservation/regeneration correlated with activation of the insulin receptor/Pi3K/Akt signaling pathway and vascular endothelial growth factor-A expression involved in maintaining β-cell mass and function.

CONCLUSIONS

Our results suggest a therapeutic role for AFSC in preserving and promoting endogenous β-cell functionality and proliferation. The protective role of AFSC is evident when stem cell transplantation is performed before severe hyperglycemia occurs, which suggests the importance of early intervention. The present study demonstrates the possible benefits of the application of a non-genetically engineered stem cell population derived from amniotic fluid for the treatment of type 1 diabetes mellitus and gives new insight on the mechanism by which the beneficial effect is achieved.

Differentiation and lineage commitment of murine embryonic stem cells into insulin producing cells

Pluripotent embryonic stem (ES) cells and induced pluripotent stem (iPS) cells recently developed in our laboratory can be used to generate the much needed insulin producing cells (IPCs) for the treatment of type 1 diabetes. However, currently available differentiation protocols generate IPCs at a very low frequency. More importantly, it is difficult to purify the IPCs from the mixed cell population due to the lack of well characterized pancreatic beta cell-specific cell surface markers. Subsequently, multiple studies have been published with limited success. A major cause for these poor results is an inadequate Pdx1 expression in the embryoid body (EB) or definitive endoderm (DE)-derived precursors. Here we investigated whether ectopic expression of pancreatic and duodenal homeobox 1 (Pdx1), an essential pancreatic transcription factor, in mouse ES cells leads to enhanced differentiation into IPCs. Here we describe a new approach for the generation of glucose responsive IPCs using ES cells ectopically expressing pancreatic and duodenal homeobox 1 (Pdx1) and paired box gene 4 (Pax4).

PDX1-engineered embryonic stem cell-derived insulin producing cells regulate hyperglycemia in diabetic mice

Background

Type 1 diabetes can be treated by the transplantation of cadaveric whole pancreata or isolated pancreatic islets. However, this form of treatment is hampered by the chronic shortage of cadaveric donors. Embryonic stem (ES) cell-derived insulin producing cells (IPCs) offer a potentially novel source of unlimited cells for transplantation to treat type 1 and possibly type 2 diabetes. However, thus far, the lack of a reliable protocol for efficient differentiation of ES cells into IPCs has hindered the clinical exploitation of these cells.

Methods

To efficiently generate IPCs using ES cells, we have developed a double transgenic ES cell line R1Pdx1AcGFP/RIP-Luc that constitutively expresses pancreatic β-cell-specific transcription factor pancreatic and duodenal homeobox gene 1 (Pdx1) as well as rat insulin promoter (RIP) driven luciferase reporter. We have established several protocols for the reproducible differentiation of ES cells into IPCs. The differentiation of ES cells into IPCs was monitored by immunostaining as well as real-time quantitative RT-PCR for pancreatic β-cell-specific markers. Pancreatic β-cell specific RIP became transcriptionally active following the differentiation of ES cells into IPCs and induced the expression of the luciferase reporter. Glucose stimulated insulin secretion by the ES cell-derived IPCs was measured by ELISA. Further, we have investigated the therapeutic efficacy of ES cell-derived IPCs to correct hyperglycemia in syngeneic streptozotocin (STZ)-treated diabetic mice. The long term fate of the transplanted IPCs co-expressing luciferase in syngeneic STZ-induced diabetic mice was monitored by real time noninvasive in vivo bioluminescence imaging (BLI).

Results

We have recently demonstrated that spontaneous in vivo differentiation of R1Pdx1AcGFP/RIP-Luc ES cell-derived pancreatic endoderm-like cells (PELCs) into IPCs corrects hyperglycemia in diabetic mice. Here, we investigated whether R1Pdx1AcGFP/RIP-Luc ES cells can be efficiently differentiated in vitro into IPCs. Our new data suggest that R1Pdx1AcGFP/RIP-Luc ES cells efficiently differentiate into glucose responsive IPCs. The ES cell differentiation led to pancreatic lineage commitment and expression of pancreatic β cell-specific genes, including Pax4, Pax6, Ngn3, Isl1, insulin 1, insulin 2 and PC2/3. Transplantation of the IPCs under the kidney capsule led to sustained long-term correction of hyperglycemia in diabetic mice. Although these newly generated IPCs effectively rescued hyperglycemic mice, an unexpected result was teratoma formation in 1 out of 12 mice. We attribute the development of the teratoma to the presence of either non-differentiated or partially differentiated stem cells.

Conclusions

Our data show the potential of Pdx1-engineered ES cells to enhance pancreatic lineage commitment and to robustly drive the differentiation of ES cells into glucose responsive IPCs. However, there is an unmet need for eliminating the partially differentiated stem cells.

Stem cells as a tool to improve outcomes of islet transplantation

The publication of the promising results of the Edmonton protocol in 2000 generated optimism for islet transplantation as a potential cure for Type 1 Diabetes Mellitus. Unfortunately, follow-up data revealed that less than 10% of patients achieved long-term insulin independence. More recent data from other large trials like the Collaborative Islet Transplant Registry show incremental improvement with 44% of islet transplant recipients maintaining insulin independence at three years of follow-up. Multiple underlying issues have been identified that contribute to islet graft failure, and newer research has attempted to address these problems. Stem cells have been utilized not only as a functional replacement for β cells, but also as companion or supportive cells to address a variety of different obstacles that prevent ideal graft viability and function. In this paper, we outline the manners in which stem cells have been applied to address barriers to the achievement of long-term insulin independence following islet transplantation.

A non-destructive culturing and cell sorting method for cardiomyocytes and neurons using a double alginate layer

A non-destructive method of collecting cultured cells after identifying their in situ functional characteristics is proposed. In this method, cells are cultivated on an alginate layer in a culture dish and released by spot application of a calcium chelate buffer that locally melts the alginate layer and enables the collection of cultured cells at the single-cell level. Primary hippocampal neurons, beating human embryonic stem (hES) cell-derived cardiomyocytes, and beating hES cell-derived cardiomyocyte clusters cultivated on an alginate layer were successfully released and collected with a micropipette. The collected cells were recultured while maintaining their physiological function, including beating, and elongated neurites. These results suggest that the proposed method may eventually facilitate the transplantation of ES- or iPS-derived cardiomyocytes and neurons differentiated in culture.

Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging

Recently, transplantation of allogeneic and autologous cells has been used for regenerative medicine. A critical issue is monitoring migration and homing of transplanted cells, as well as engraftment efficiency and functional capability in vivo. Monitoring of superparamagnetic iron oxide (SPIO) particles by magnetic resonance imaging (MRI) has been used in animal models and clinical settings to track labeled cells. A major limitation of MRI is that the signals do not show biological characteristics of transplanted cells in vivo. Bone marrow mesenchymal stem cells (MSCs) have been extensively investigated for their various therapeutic properties, and exhibit the potential to differentiate into cells of diverse lineages. In this study, cynomolgus monkey MSCs (cMSCs) were labeled with Molday ION Rhodamine-B™ (MIRB), a new SPIO agent, to investigate and characterize the biophysical and MRI properties of labeled cMSCs in vitro and in vivo. The results indicate that MIRB is biocompatible and useful for cMSCs labeling and cell tracking by multimodality imaging. Our method is helpful for detection of transplanted stem cells in vivo, which is required for understanding mechanisms of cell therapy.

Molecular imaging: a promising tool to monitor islet transplantation

Replacement of insulin production by pancreatic islet transplantation has great potential as a therapy for type 1 diabetes mellitus. At present, the lack of an effective approach to islet grafts assessment limits the success of this treatment. The development of molecular imaging techniques has the potential to fulfill the goal of real-time noninvasive monitoring of the functional status and viability of the islet grafts. We review the application of a variety of imaging modalities for detecting endogenous and transplanted beta-cell mass. The review also explores the various molecular imaging strategies for assessing islet delivery, the metabolic effects on the islet grafts as well as detection of immunorejection. Here, we highlight the use of combined imaging and therapeutic interventions in islet transplantation and the in vivo monitoring of stem cells differentiation into insulin-producing cells.

Stem cells in brain diseases: From cell replacement to disease modeling

Neurological diseases are recognized as one of the most significant burdens of the modern society. Therefore, a new therapeutic approach applicable to nervous system represents priority of today’s medicine. A rapid development of stem cell technology in the last two decades introduced a possibility to regenerate disease-affected nervous tissue. In this vein, stem cells are envisioned as a replacement for lost neurons, a source of trophic support, a therapeutic vehicle, and as a tool for in vitro modeling. This article reviews the current concepts in stem cell-based therapy of neurological diseases and comments ongoing efforts aiming at clinical translation.