Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice. Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells.     

再生胰腺提取物诱导人羊膜间充质干细胞定向分化为胰岛素分泌细胞

利用天然生物诱导剂大鼠再生胰腺提取物(Rgenerating pancreatic extract,RPE)定向诱导人羊膜间充质干细胞(Human amniotic mesenchymal stem cells,hAMSCs)向胰岛素分泌细胞分化。切除大鼠60%胰腺刺激胰腺再生,而后制备RPE,以终浓度为20 mg/L的RPE诱导hAMSCs。实验通过形态学鉴定、双硫腙染色、免疫荧光分析、RT-PCR基因检测和高糖刺激胰岛素分泌等实验鉴定细胞诱导结果。实验结果显示P3代hAMSCs经RPE诱导后形态变化明显,诱导15 d后细胞呈簇状生长,经双硫腙染色可见棕红色细胞团;免疫荧光染色结果显示诱导细胞呈胰岛素阳性表达;RT-PCR实验证明诱导细胞阳性表达人胰岛相关基因Pdx1和insulin;高糖刺激实验证明培养液中有胰岛素成分产生,且分泌量随刺激时间的延长先增加而后趋于稳定。实验结果表明hAMSCs在体外经RPE诱导可以分化为胰岛素分泌细胞。     

Therapeutic effects of menstrual blood-derived endometrial stem cells on mouse models of streptozotocin-induced type 1 diabetes

BACKGROUND Type 1 diabetes(T1D),a chronic metabolic and autoimmune disease,seriously endangers human health.In recent years,mesenchymal stem cell(MSC)transplantation has become an effective treatment for diabetes.Menstrual bloodderived endometrial stem cells(MenSC),a novel MSC type derived from the decidual endometrium during menstruation,are expected to become promising seeding cells for diabetes treatment because of their noninvasive collection procedure,high proliferation rate and high immunomodulation capacity.AIM To comprehensively compare the effects of MenSC and umbilical cord-derived MSC(UcMSC)transplantation on T1D treatment,to further explore the potential mechanism of MSC-based therapies in T1D,and to provide support for the clinical application of MSC in diabetes treatment.METHODS A conventional streptozotocin-induced T1D mouse model was established,and the effects of MenSC and UcMSC transplantation on their blood glucose and serum insulin levels were detected.The morphological and functional changes in the pancreas,liver,kidney,and spleen were analyzed by routine histological and immunohistochemical examinations.Changes in the serum cytokine levels in the model mice were assessed by protein arrays.The expression of target proteins related to pancreatic regeneration and apoptosis was examined by western blot.RESULTS MenSC and UcMSC transplantation significantly improved the blood glucose and serum insulin levels in T1D model mice.Immunofluorescence analysis revealed that the numbers of insulin+and CD31+cells in the pancreas were significantly increased in MSC-treated mice compared with control mice.Subsequent western blot analysis also showed that vascular endothelial growth factor(VEGF),Bcl2,Bcl-xL and Proliferating cell nuclear antigen in pancreatic tissue was significantly upregulated in MSC-treated mice compared with control mice.Additionally,protein arrays indicated that MenSC and UcMSC transplantation significantly downregulated the serum levels of interferonγand tumor necrosis factorαand upregulated the serum levels of interleukin-6 and VEGF in the model mice.Additionally,histological and immunohistochemical analyses revealed that MSC transplantation systematically improved the morphologies and functions of the liver,kidney,and spleen in T1D model mice.CONCLUSION MenSC transplantation significantly improves the symptoms in T1D model mice and exerts protective effects on their main organs.Moreover,MSC-mediated angiogenesis,antiapoptotic effects and immunomodulation likely contribute to the above improvements.Thus,MenSC are expected to become promising seeding cells for clinical diabetes treatment due to their advantages mentioned above.     

The reversal of hyperglycemia after transplantation of mouse embryonic stem cells induced into early hepatocyte-like cells in streptozotocin-induced diabetic mice

Cellular replacement therapy is a potential therapeutic strategy for diabetes. In this study, we investigated the effect of transplantation of induced mouse embryonic stem cells (mESCs) into endoderm and early hepatocyte-like cells in streptozotocin (STZ)-diabetic mice. After embryoid body (EB) formation from mESC, the EBs were cultured in the presence of dexamethasone (DEX) and insulin for 4 days then was added acidic fibroblast growth factor (aFGF), hepatocyte growth factor (HGF) and oncostatin M (OSM) for 10 days, respectively. Blood glucose levels, intraperitoneal glucose tolerance (IGT) test and islet histology were assessed. The result revealed that transplantation of induced mESCs into early hepatocyte-like cells could repair pancreatic islets of control group. Blood glucose levels and intraperitoneal glucose tolerance test were significantly improved in test group compared to control group. Furthermore, there was significant increase in the number of islets in test group compared to control group. The findings declare that induced mESCs into endoderm and early hepatocyte-like cells, are appropriate candidate for regenerative therapy of pancreatic islets in type I diabetes.     

Transplantation of human umbilical cord blood cells improves glycemia and glomerular hypertrophy in type 2 diabetic mice

Recent in vitro and in vivo studies have shown that either animal- or human-derived embryonic stem cells can differentiate into insulin-secreting cells and lower blood glucose levels. However, studies utilizing human umbilical cord blood (HUCB) mononuclear cells to improve blood glucose levels in diabetic animals have received little attention. In this study, we examined the effect of transplanted HUCB mononuclear cells on blood glucose levels, survival, and renal pathology in obese mice with spontaneous development of type 2 diabetes. The results show that injection of HUCB mononuclear cells into orbital plexus of mice caused improvement not only in blood glucose levels and survival rate but also normalization of glomerular hypertrophy and tubular dilatation. Thus, transplantation of HUCB mononuclear cells appears to be another modality of stem cell therapy in diabetes mellitus.     

Differential effect of activin on mouse embryonic stem cell differentiation in insulin-secreting cells under nestin-positive selection and spontaneous differentiation protocols

Parallel to the importance of the development of cell therapies to treat diabetes is the production of sufficient numbers of pancreatic endocrine cells that function like primary islets. To increase the efficiency of endocrine pancreatic-like cell differentiation from mouse embryonic stem cells (ESCs), we applied activin-B to nestin-positive selection (protocol 1) and spontaneous differentiation (protocol 2) in different groups including: [A] activin-B, or [B] basic fibroblast growth factor (bFGF), and/or [C] activin-B+bFGF. The differentiated cells expressed most pancreatic-related genes. The number of insulin- and C peptide-positive cells, as well as dithizone-positive clusters in group A of protocol 1 was higher than in the other groups. Significant insulin concentrations in protocol 1 were produced when glucose was added to the medium, in comparison with protocol 2. Moreover, insulin release was increased significantly in group A of protocol 1 even with lower glucose. In conclusion, Addition of activin-B in a nestin-positive selection protocol increased the insulin-secreting cells in comparison with the same protocol with bFGF and/or spontaneous differentiation in presence of bFGF and/or activin-B alone. However, improvements of the current method are required to generate a sufficient source of true beta-cells for the treatment of diabetes mellitus.     

Generation of insulin-secreting cells from pancreatic acinar cells of animal models of type 1 diabetes

We recently found that pancreatic acinar cells isolated from normal adult mouse can transdifferentiate into insulin-secreting cells in vitro. Using two different animal models of type 1 diabetes, we show here that insulin-secreting cells can also be generated from pancreatic acinar cells of rodents in the diabetic state with absolute insulin deficiency. When pancreatic acinar cells of streptozotocin-treated mice were cultured in suspension in the presence of epidermal growth factor and nicotinamide under low-serum condition, expressions of insulin genes gradually increased. In addition, expressions of other pancreatic hormones, including glucagon, somatostatin, and pancreatic polypeptide, were also induced. Analysis by the Cre/loxP-based direct cell lineage tracing system revealed that these newly made cells originated from amylase-expressing pancreatic acinar cells. Insulin secretion from the newly made cells was significantly stimulated by high glucose and other secretagogues. In addition, insulin-secreting cells were generated from pancreatic acinar cells of Komeda diabetes-prone rats, another animal model of type 1 diabetes. The present study demonstrates that insulin-secreting cells can be generated by transdifferentiation from pancreatic acinar cells of rodents in the diabetic state and further suggests that pancreatic acinar cells represent a potential source of autologous transplantable insulin-secreting cells for treatment of type 1 diabetes.     

人脐带间充质干细胞对1型糖尿病鼠肝脏损伤的保护作用

目的探讨人脐带间充质干细胞（hUCMSCs）对初发1型非肥胖型糖尿病（NOD）小鼠肝脏损伤的保护作用。 方法雌性NOD小鼠共33只,饲养9周后,将成模的21只小鼠随机分为糖尿病组和干细胞组,每组10只,其中干细胞（MSCs）组发病后第3天尾静脉注射hUCMSCs 1?次;另取10只未发病小鼠为正常对照组。各组小鼠每周检测随机血糖（GLU）水平,8周后处死小鼠,取肝脏,HE染色后观察肝脏结构改变,ELISA法检测糖基化终末产物（AGEs）水平,Real-time PCR法检测糖基化终末产物受体（RAGE）、NF-κB P65、白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α） mRNA的表达水平。采用单因素方差分析和SNK-q检验进行统计学分析。 结果MSCs治疗8周后,MSCs组小鼠随机血糖（8.46±1.37）mmol/L比T1DM组（32.82±0.59）?mmol/L降低,差异具有统计学意义（P < 0.05）。同时T1DM组肝脏细胞形态异常,炎症细胞浸润,而MSCs组的较T1DM组明显改善。MSCs组小鼠肝脏组织的AGEs浓度（0.72±0.10）μg/ml低于T1DM组（1.35±0.22）μg/ml;同时MSCs组的NF-κB P65、IL-6、TNF-α、RAGE mRNA水平（分别为10.08±1.94、9.31±1.67、11.92±1.82、3.87±0.27）,均低于T1DM组（分别为15.46±3.09、18.04±1.69、22.12±3.23、5.12±0.26）,差异具有统计学意义（P < 0.05）。 结论hUCMSCs可以降低糖尿病小鼠血糖水平,改善肝脏微观病理状态,降低AGEs浓度及某些炎性因子的水平以减轻肝脏损伤。     

利用成体干细胞治疗糖尿病

糖尿病是一类严重的代谢疾病, 正危害着世界上越来越多人口的健康。胰岛移植是一种治疗糖尿病的有效方法,却因供体缺乏和移植后免疫排斥问题制约了其广泛应用。干细胞为具有强增殖能力和多向分化潜能的细胞, 是利用细胞替代疗法治疗重大疾病的细胞来源之一, 其中成体干细胞因不存在致瘤性及伦理道德问题而被人们寄予厚望。成体胰腺干细胞在活体损伤及离体培养条件下均能产生胰岛素分泌细胞, 肝干细胞、骨髓干细胞和肠干细胞等在特定离体培养条件下或经过遗传改造后也均可产生胰岛素分泌细胞, 将这些干细胞来源的胰岛素分泌细胞移植到模型糖尿病小鼠中可以治疗糖尿病。因而, 成体干细胞可以为细胞替代疗法治疗糖尿病提供丰富的胰岛供体来源。     

Generation of insulin-producing cells from PDX-1 gene-modified human mesenchymal stem cells

Islet cell replacement is considered as the optimal treatment for type I diabetes. However, the availability of human pancreatic islets for transplantation is limited. Here, we show that human bone marrow-derived mesenchymal stem cells (hMSCs) could be induced to differentiate into functional insulin-producing cells by introduction of the pancreatic duodenal homeobox-1 (PDX-1). Recombinant adenoviral vector was used to deliver PDX-1 gene into hMSCs. After being infected with Ad-PDX-1, hMSCs were successfully induced to differentiate into insulin-secreting cells. The differentiated PDX-1+ hMSCs expressed multiple islet-cell genes including neurogenin3 (Ngn3), insulin, GK, Glut2, and glucagon, produced and released insulin/C-peptide in a weak glucose-regulated manner. After the differentiated PDX-1+ hMSCs were transplanted into STZ-induced diabetic mice, euglycemia can be obtained within 2 weeks and maintained for at least 42 days. These findings validate the hMSCs model system as a potential basis for enrichment of human beta cells or their precursors, and a possible source for cell replacement therapy in diabetes.     

Characterizing the degeneration of nuclear membrane and mitochondria of adipose-derived mesenchymal stem cells from patients with type II diabetes

Regenerative therapeutic approaches involving the transplantation of stem cells differentiated into insulin-producing cells are being studied in patients with rapidly progressing severe diabetes. Adipose-derived mesenchymal stem cells have been reported to have varied cellular characteristics depending on the biological environment of the location from which they were harvested. However, the characteristics of mesenchymal stem cells in type II diabetes have not been clarified. In this study, we observed the organelles of mesenchymal stem cells from patients with type II diabetes under a transmission electron microscope to determine the structure of stem cells in type II diabetes. Transmission electron microscopic observation of mesenchymal stem cells from healthy volunteers (N-ADSC) and those from patients with type II diabetes (T2DM-ADSC) revealed enlarged nuclei and degenerated mitochondrial cristae in T2DM-ADSCs. Moreover, T2DM-ADSCs were shown to exhibit a lower expression of Emerin, a constituent protein of the nuclear membrane, and a decreased level of mitochondrial enzyme activity. In this study, we successfully demonstrated the altered structure of nuclear membrane and the decreased mitochondrial enzyme activity in adipose-derived mesenchymal cells from patients with type II diabetes. These findings have contributed to the understanding of type II diabetes-associated changes in mesenchymal stem cells used for regenerative therapy.     

Insulin-producing cells from human pancreatic islet-derived progenitor cells following transplantation in mice

Stem/progenitor cells hold promise for alleviating/curing type 1 diabetes due to the capacity to differentiate into functional insulin-producing cells. The current study aims to assess the differentiation potential of human pancreatic IPCs (islet-derived progenitor cells). IPCs were derived from four human donors and subjected to more than 2000-fold expansion before turning into ICCs (islet-like cell clusters). The ICCs expressed ISL-1 Glut2, PDX-1, ngn3, insulin, glucagon and somatostatin at the mRNA level and stained positive for insulin and glucagon by immunofluorescence. Following glucose challenge in vitro, C-peptide was detected in the sonicated ICCs, instead of in the conditioned medium. To examine the function of the cells in vivo, IPCs or ICCs were transplanted under the renal capsule of immunodeficient mice. One month later, 19 of 28 mice transplanted with ICCs and 4 of 14 mice with IPCs produced human C-peptide detectable in blood, indicating that the in vivo environment further facilitated the maturation of ICCs. However, among the hormone-positive mice, only 9 of 19 mice with ICCs and two of four mice with IPCs were able to secrete C-peptide in response to glucose.     

Electrospun poly-l-lactic acid/polyvinyl alcohol nanofibers improved insulin-producing cell differentiation potential of human adipose-derived mesenchymal stem cells

Combination of adipose-derived mesenchymal stem cells (ADSCs) and synthetic materials in terms of pancreatic tissue engineering can be considered as a treatment of diabetes. This study aimed to evaluate the differentiation of human ADSCs to pancreatic cells on poly-l -lactic acid/polyvinyl alcohol (PLLA/PVA) nanofibers as a three-dimensional (3D) scaffold. Mesenchymal stem cells (MSCs) were characterized for mesenchymal surface markers by flow cytometry. Then ADSCs were seeded on 3D scaffolds and treated with pancreatic differentiation medium. Immunostaining assay showed that ADSCs were very efficiently differentiated into a relatively homogeneous population of insulin-producing cells. Moreover, real-time RT-PCR results revealed that pancreas-specific markers were highly expressed in 3D scaffolds compared with their expression in tissue culture plates and this difference in expression level was significant. In addition, insulin and C-peptide secreted in response to varying concentrations of glucose in the 3D scaffold group was significantly higher than that in 2D culture. The results of the present study confirmed that PLLA/PVA scaffold seeded with ADSCs could be a suitable option in pancreatic tissue engineering.     

Placenta-derived multipotent stem cells induced to differentiate into insulin-positive cells

In the present study, we successfully isolated PDMSCs from human placental tissues. The RT-PCR results show that PDMSCs preserved the genetic characteristics of the primitive embryonic stage--Oct-4 and Nanog. By using serum-free medium supplemented essential growth factors and induction medium culture for 4 weeks, a monolayer of spindle-like PDMSCs gradually formed 3D spheroid bodies (SB-PDMSCs). By using real-time RT-PCR, early mRNA expressions of Pdx1, as well as the Sox17 and Foxa2 genes, were observed to be significantly activated in SB-PDMSCs, followed by the expression of mature pancreas-related genes (insulin, glucagon, and somatostatin). The high insulin content of SB-PDMSCs was further confirmed by ELISA assay, and the glucose dependency was demonstrated by the corresponding insulin secretion level. In a transplantation study of streptozotocin-pretreated nude mice, the restoration of normoglycemia in the SB-PDMSC treated group was further observed. In conclusion, these results indicate that PDMSCs are an excellent source for the induced differentiation of well-functioning insulin-positive cells. The potential of these insulin producing cells derived from PDMSCs was also demonstrated functionally by the demonstration of secreted insulin in vitro and effective control of blood glucose levels in vivo.     

Human mesenchymal stem cells and renal tubular epithelial cells differentially influence monocyte-derived dendritic cell differentiation and maturation

Mesenchymal stem cells (MSCs) possess immunosuppressive properties. But also fully differentiated human renal tubular epithelial cells (RTECs) are able to modulate T-cell proliferation in vitro. In this study we compared two MSC populations, human adipose derived stem cells (ASCs) and human amniotic mesenchymal stromal cells (hAMSCs), and RTECs regarding their potential to inhibit monocyte-derived dendritic cell (DC) differentiation and maturation in indirect co-culture.In the presence of hAMSCs and RTECs, monocytes stimulated to undergo DC differentiation were inhibited to acquire surface phenotype of immature and mature DCs. In contrast, ASCs showed only limited suppressive capacity. Secretion of IL-12p70 was suppressed in hAMSC co-cultures and high IL-10 levels were detected in all co-cultures. Prostaglandin E₂ was found in ASC and hAMSC co-cultures, whereas soluble human leukocyte antigen-G was highly elevated only in RTEC co-cultures. Thus, inhibition of DC generation by MSCs and RTECs might be mediated by different soluble factors.