Establishing a human pancreatic stem cell line and transplanting induced pancreatic islets to reverse experimental diabetes in rats

Resveratrol controlled the fate of porcine pancreatic stem cells through the Wnt/β-catenin signaling pathway mediated by Sirt1

Porcine pancreatic stem cells (PSCs) are considered promising transplant materials that may be used to treat diabetes, but some problems, such as insufficient cell number and low differentiation efficiency, should be solved before its clinical application. Resveratrol is a natural polyphenolic compound that can alleviate the complications of diabetes. In this study, we aimed to explore the specific effect of resveratrol on porcine PSCs. We treated porcine PSCs with 10 μM, 25 μM resveratrol to explore the effect of resveratrol on porcine PSCs. We found that 10 μM resveratrol improved the proliferation of porcine PSCs, increased the expression of A-β-catenin (active β-catenin), Pcna, C-Myc, Bcl-2 and sirtuin-1 (Sirt1), and decreased the expression of P53, Caspase3. While 25 μM resveratrol had almost opposite effect compared with 10 μM resveratrol group. The utilization of Dickkopf-related protein 1 (DKK1, Wnt signaling pathway inhibitor) and nicotinamide (Sirt1 inhibitor) suggested that resveratrol regulated cell proliferation by controlling Wnt signaling pathway and this effect was mediated by Sirt1. Our results further revealed that 10 μM resveratrol promoted the formation of β-like cells regulated by Wnt/β-catenin signal pathway. Relatively low-dose resveratrol could improve porcine PSCs fate. It lays theoretical foundation for diabetes treatment with cell transplantation in future.

Morphological characteristics and identification of islet-like cells derived from rat adipose-derived stem cells cocultured with pancreas adult stem cells

Diabetes is a significant public health problem that can be treated with insulin therapy; however, therapies designed to cure diabetes are limited. The goal of the current study was to assess the potential for curative treatment of diabetes using adipose-derived stem cells (ADSCs). To achieve this goal, the differentiation of rat ADSCs into pancreatic islet-like cells induced by coculture with pancreatic adult stem cells (PASCs) was characterized. Differentiation of ADSCs into islet-like cells induced by coculturing was determined morphologically, as well as by the assessment of islet cell markers using dithizone staining, immunohistochemistry, RT-PCR, qPCR, and western blotting. The results showed that ADSCs formed islet-like round cell masses after coculture with PASCs. These differentiated cells were shown to be positive for islet cell markers, including dithizone incorporation; PDX1, CK19 and Nestin by immunohistochemistry, and insulin, PDX1 and glucagon expression by RT-PCR. Differentiated ADSCs induced by coculturing also expressed insulin at the mRNA and protein level, with the level of insulin mRNA expression in cocultured ADSCs being 0.05 times greater than that of PASCs (P < 0.05). Taken together, our results demonstrate that ADSCs can be induced to differentiate into islet-like cells by coculture with PASCs; thus these cells can be used for transplantation, providing a theoretical foundation for the treatment of diabetes using this approach.

Generation of mouse models for type 1 diabetes by selective depletion of pancreatic beta cells using toxin receptor-mediated cell knockout

By using the toxin receptor-mediated cell knockout (TRECK) method, we have generated two transgenic (Tg) murine lines that model type 1 (insulin-dependent) diabetes. The first strain, C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg, carries the diphtheria toxin receptor (hDTR) driven by the human insulin gene promoter, while the other strain, C57BL/6-ins2(BAC)-TRECK-Tg, expresses hDTR cDNA under the control of the mouse insulin II gene promoter. With regard to the C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg strain, only one of three Tg strains exhibited proper expression of hDTR in pancreatic β cells. By contrast, hDTR was expressed in the pancreatic β cells of all four of the generated C57BL/6-ins2(BAC)-TRECK-Tg strains. Hyperglycemia, severe ablation of pancreatic β cells and depletion of serum insulin were observed within 3days after the administration of diphtheria toxin (DT) in these Tg mice. Subcutaneous injection of a suitable dosage of insulin was sufficient for recovery from hyperglycemia in all of the examined strains. Using the C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg model, we tried to perform regenerative therapeutic approaches: allogeneic transplantation of pancreatic islet cells from C57BL/6 and xenogeneic transplantation of CD34(+) human umbilical cord blood cells. Both approaches successfully rescued C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg mice from hyperglycemia caused by DT administration. The high specificity with which DT causes depletion in pancreatic β cells of these Tg mice is highly useful for diabetogenic research.

Induced autologous stem cell transplantation for treatment of rabbit type 1 diabetes

We have examined the effects of induced autologous stem cells on blood sugar levels in a rabbit model of type 1 diabetes. Rabbit skin fibroblasts were induced to dedifferentiate into multipotent stem cells, and were transplanted into the treatment group via the pancreatic artery. After the fibroblasts had been induced for 72 h, some of them became multipotent stem cells. Four weeks after cell transplantation, blood glucose levels of the induced stem cell treatment group were significantly lower. The plasma insulin and plasma C-peptide levels of the treated group were significantly increased (P < 0.05). The shape and number of islets was different. In the control group, induced cell treatment group and non-induced cell treatment group. In the control group, islet β-cell nucleoli were obvious, and cell volumes were larger with more abundant cytoplasm. The rough endoplasmic reticulum was well-developed and a large number of secretory granules could be seen within the cytoplasm. In the induced cell treatment group, islet β cells were scattered, and their nuclei were oval and slightly irregular in shape. The cytoplasm of these cells contained a nearly normal number of secretory granules. In the non-induced cell treatment group, islet β-cells were atrophied and cell volumes were reduced. Cytoplasmic endocrine granules were significantly reduced or absent. In conclusion, treatment with induced multipotent stem cells can reduce blood sugar levels, improve islet cell function, and repair damaged pancreas in a rabbit model of type 1 diabetes.

Characterizing the induction of diabetes in juvenile cynomolgus monkeys with different doses of streptozotocin

Juvenile (2-23 years old) cynomolgus monkeys are frequently used as recipients in non-human primate islet transplantation studies. The aim of this study was to examine the effects of different doses of streptozotocin (STZ), and find the optimal dose for inducing diabetes in these monkeys. Fifteen juvenile (2-3 years old) cynomolgus monkeys were separated into three groups and administered with different doses of STZ (100, 68 or 60 mg kg(-1)). Basal and glucose-stimulated blood glucose, insulin, and C-peptide levels, as well as body weights were monitored. Hepatic and renal function tests and pancreatic immunohistochemistry were performed before and after STZ treatment. Monkeys treated with both 100 and 68 mg kg(-1) of STZ exhibited continuous hyperglycemia, which coincided with a nearly complete loss of islet β-cells. Two monkeys received 60 mg kg(-1) of STZ, but only one became completely diabetic. During the first week following STZ treatment, hepatic and renal function slightly increased in these three groups. However, 24 hours post-STZ, serum total bile acid levels were significantly increased in monkeys treated with 100 mg kg(-1) than those treated with 68 mg kg(-1) of STZ (P<0.05). These data suggest that 100 mg kg(-1) and 68 mg kg(-1) of STZ can safely induce diabetes in cynomolgus monkeys aged 2-3 years, but 68 mg kg(-1) of STZ, rather than 100 mg kg(-1) of STZ, may be more appropriate for inducing diabetes in these monkeys. Furthermore, body surface area, rather than body weight, was a more reliable determinant of dosage, where 700 mg m(-2) of STZ should be the lower limit for inducing diabetes in juvenile monkeys.

Pancreatic islet derived stem cells can express co-stimulatory molecules of antigen-presenting cells

BACKGROUND

Antigen-presenting cells (APCs) are crucial intermediates in the generation of both innate and specific immune responses. It has long been understood that some APCs are resident in islets in situ as well as after isolation. Our aim was to investigate the presence of molecules involved in antigen presentation in rat pancreatic islet-derived stem cells (PI-SCs).

METHODS

We used immunocytochemistry and reverse transcription polymerization chain reaction to study immunophenotypic characteristics; pluripotent-related gene expressions; transcripts coding for antigen-presenting surface proteins CD40, CD80, CD86; and major histocompatibility complex class II in addition to genes with known antiapoptotic functions including mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2), tumor necrosis factor alpha-induced protein 3 (TNFAIP3) interacting protein 1 (TNIP1) and BCL3 of the PI-SCs.

RESULTS

Rat PI-SCs were negative for CD45 as demonstrated by flow cytometry and for CD31, CD34, and CD71 as demonstrated by immunocytochemistry. Therefore, there was no evidence of hematopoietic precursors in the cultures. OCT4, SOX2, and REX1 were expressed by rat PI-SCs. We determined the expression of genes for antigen-presenting surface proteins CD40 and CD80, and genes with known antiapoptotic functions including MAPKAPK2, TNIP1 and BCL3, besides the surface protein, CD80, by flow cytometry.

CONCLUSION

Expression of these genes by rat PI-SCs implied that they could be involved in the regulation of immunity in islets, highlighting the influence of protective role-playing antiapoptotic mechanisms on pancreatic islet cells. This study offers the potential to understand the molecular mechanisms of a devastating disease, type-1 diabetes mellitus.