Evaluation of islets derived from human fetal pancreatic progenitor cells in diabetes treatment

In Vitro Human Fetal Pancreatic Islets to Redefine Pancreatic Research

BACKGROUND

In vitro studies with human fetal islets of different gestational ages (GA) would be a great tool to generate information on the developmental process of the islets as this would help to recontextualize diabetes research and clinical practice. Pancreatic islets from human cadavers and other animal species are extensively researched to explore their suitability for islet transplantation procedure, one of the upcoming treatment strategies for insulin-dependent diabetes mellitus. Although human fetal islets are also considered for islet transplantation, ethical issues and limited knowledge constraints their use. The fetal islets could be explored to address the information lacunae on the maturity process of pancreatic islets and the endocrine-exocrine signaling mechanisms.

AIM

This study aimed to assess the feasibility of isolating viable islets and study the cytoarchitecture of the fetal pancreas of GA 22-29 weeks, not reported otherwise.

METHODOLOGY

Pancreas obtained from the aborted fetuses of GA 22-29 weeks were subjected to collagenase digestion and were further cultured to determine the viability in vitro. Parameters assessed were expression of markers for endocrine cell lineages and insulin release to glucose challenge.

RESULTS

Islets were viable in vitro and islets were shown to maintain cues for post-digestion re-aggregation and expansion in culture. The immunofluorescent staining showed islets of varying sizes, homogenous cell clusters aggregating to form heterogenous cell clusters, otherwise not reported for this GA. On stimulation with different concentrations of glucose (2.8 and 28 mM), the fetal islets in the culture exhibited insulin release, and this response confirmed their viability in vitro.

CONCLUSION

Our findings showed that viable islets could be isolated and cultured in vitro for further in-depth studies to explore their proliferative potential as well as for the identification of pancreatic progenitors, a good strategy to take forward.

Adipocyte-derived stem cell-based gene therapy upon adipogenic differentiation on microcarriers attenuates type 1 diabetes in mice

BACKGROUND

Insulin replenishment is critical for patients with type 1 diabetes; however, current treatments such as pancreatic islet transplantation and insulin injection are not ideal. In addition to stem cell or gene therapy alone, stem cell combined with gene therapy may provide a new route for insulin replenishment, which could avoid an autoimmune reaction against differentiated β cells or systematic viral vector injection.

METHODS

In this study, human adipocyte-derived stem cells (ADSCs) were transducted with lentiviral vectors expressing a furin-cleavable insulin gene. The expression levels of insulin were measured before and after adipogenic differentiation in the presence or absence of an adipocyte-specific promoter AP2. In vitro proliferation and in vivo survival of cells were examined on cytodex and cytopore microcarriers. The effect of ADSC-based gene therapy upon adipogenic differentiation on microcarriers was evaluated in the streptozotocin-induced type 1 diabetic mouse model.

RESULTS

We found that differentiation of ADSCs into adipocytes increased insulin expression under the EF1 promoter, while adipocyte-specific AP2 promoter further increased insulin expression upon differentiation. The microcarriers supported cell attachment and proliferation during in vitro culture and facilitate cell survival after transplantation. Functional cells on the cytopore 1 microcarrier formed tissue-like structures and alleviated hyperglycemia in the type 1 diabetic mice after subcutaneous injection.

CONCLUSIONS

Our results indicated that differentiation of ADSC and tissue-specific promotors may enhance the expression of therapeutic genes. The use of microcarriers may facilitate cell survival after transplantation and hold potential for long-term cell therapy.

Current approaches in regenerative medicine for the treatment of diabetes: introducing CRISPR/CAS9 technology and the case for non-embryonic stem cell therapy

Type 1 diabetes mellitus (T1DM) is an autoimmune disorder in which the body destroys its pancreatic β cells. Since these cells are responsible for insulin production, dysfunction or destruction of these cells necessitates blood glucose control through exogenous insulin shots. Curative treatment involves pancreas transplantation, but due to the incidence of transplant rejection and complications associated with immunosuppression, alternatives are being explored. Despite facing clinical challenges and issues with public perception, the field of regenerative stem cell therapy shows great promise for the treatment of diabetes. The idea of harnessing pluripotency to derive cells and tissues with characteristics of choice is astounding but feasible, and this review seeks to determine which method of stem cell derivation is preferable for diabetes treatment. In this report, we outline the methods for deriving human embryonic stem cells (hESCs), induced pluripotent stem cells (iPSCs), and adult stem cells or progenitor cells to generate functional islet cells and related tissues. We discuss the specific uses and advantages of each method, and we comment on the ethics and public perceptions surrounding these methods and how they may affect the future of stem cell research. For the reasons outlined in this paper, we believe that non-embryonic stem cell lines, including iPSCs, somatic cell nuclear transfer lines, and adult tissue derived stem cells, offer the highest therapeutic potential for treating diabetes.

Human Proislet Peptide Promotes Pancreatic Progenitor Cells to Ameliorate Diabetes Through FOXO1/Menin-Mediated Epigenetic Regulation

We investigated how human proislet peptide (HIP) regulates differentiation of human fetus-derived pancreatic progenitor cells (HFPPCs) and explored the potential link between HIP signaling and the menin pathway, which is key to regulating pancreatic islet differentiation. The data show that HIP promoted expression of proislet transcription factors (TFs), including PDX-1, MAFA, and NKX6.1, as well as other maturation markers of β-cells, such as insulin, GLUT2, KIR6.2, SUR1, and VDCC. Moreover, HIP increased insulin content and promoted the ability of HFPPCs to normalize blood glucose in diabetic mice. HIP inhibited the TF FOXO1 by increasing AKT-mediated phosphorylation. HIP-induced repression of FOXO1 suppressed menin expression, leading to reducing menin binding to the promoter of the three key proislet TFs, decreasing recruitment of H3K9 methyltransferase SUV39H1, and thus reducing repressive H3K9me3 at the promoter. These coordinated actions lead to increased expression of the proislet TFs, resulting in induction of HFPPC differentiation. Consistently, constitutive activation of FOXO1 blocks HIP-induced transcription of these TFs. Together, these studies unravel the crucial role of the HIP/AKT/FOXO/menin axis in epigenetically controlling expression of proislet TFs, regulating the differentiation of HFPPCs, and normalizing blood glucose in diabetic mice.

Treatment of gingival defects with gingival mesenchymal stem cells derived from human fetal gingival tissue in a rat model

Background

The study aimed to evaluate the efficacy and safety of gingival mesenchymal stem cells (GMSCs) from human fetal gingival tissue used for treating gingival defects in a rat model.

Methods

GMSCs were isolated from human fetal gingival tissue and identified by flow cytometry for nestin, Oct4, vimentin, NANOG, CD105, and CD90. The immunogenicity of GMSCs was analyzed by mixed lymphocyte reactions; the tumorigenicity of GMSCs was evaluated by xenotransplanting into nude mice. The gingival defect animal model was established by mechanical resection in rats. GMSCs were transplanted into the defective area, and the regeneration of gingival tissue was observed twice weekly. Four weeks after transplantation, the gingival tissue was surgically cut down, and the graft was analyzed by immunohistochemistry staining for human mitochondrial antigens and rat CD3 and CD20.

Results

GMSCs from human fetal gingival tissue positively expressed nestin, Oct4, vimentin, NANOG, CD105, and CD90. There was no cell aggregation after mixed lymphocyte reactions, and interleukin-2 did not increase. Inoculation of GMSCs into nude mice for 6 months showed no tumor formation. GMSCs were transplanted into the gingiva defects of rats. One week after transplantation, the defect area was reduced, and after 3 weeks the morphology and color of local gingival tissue was similar to normal gingival tissue, and gingival height was the same as the normal control group.

Conclusions

Using GMSCs from human fetal gingival tissue to treat gingival defects is a safe and effective innovative treatment method.

FoxO1 inhibition promotes differentiation of human embryonic stem cells into insulin producing cells

Insulin-producing cells (IPCs) derived from human embryonic stem cells (hESCs) hold great potential for cell transplantation therapy in diabetes. Tremendous progress has been made in inducing differentiation of hESCs into IPCs in vitro, of which definitive endoderm (DE) protocol mimicking foetal pancreatic development has been widely used. However, immaturity of the obtained IPCs limits their further applications in treating diabetes. Forkhead box O1 (FoxO1) is involved in the differentiation and functional maintenance of murine pancreatic β cells, but its role in human β cell differentiation is under elucidation. Here, we showed that although FoxO1 expression level remained consistent, cytoplasmic phosphorylated FoxO1 protein level increased during IPC differentiation of hESCs induced by DE protocol. Lentiviral silencing of FoxO1 in pancreatic progenitors upregulated the levels of pancreatic islet differentiation-related genes and improved glucose-stimulated insulin secretion response in their progeny IPCs, whereas overexpression of FoxO1 showed the opposite effects. Notably, treatment with the FoxO1 inhibitor AS1842856 displayed similar effects with FoxO1 knockdown in pancreatic progenitors. These effects were closely associated with the mutually exclusive nucleocytoplasmic shuttling of FoxO1 and Pdx1 in the AS1842856-treated pancreatic progenitors. Our data demonstrated a promising effect of FoxO1 inhibition by the small molecule on gene expression profile during the differentiation, and in turn, on determining IPC maturation via modulating subcellular location of FoxO1 and Pdx1. Therefore, we identify a novel role of FoxO1 inhibition in promoting IPC differentiation of hESCs, which may provide clues for induction of mature β cells from hESCs and clinical applications in regenerative medicine.

Systematic single-cell analysis provides new insights into heterogeneity and plasticity of the pancreas

BACKGROUND

Diabetes mellitus is characterized by loss or dysfunction of insulin-producing β-cells in the pancreas, resulting in failure of blood glucose regulation and devastating secondary complications. Thus, β-cells are currently the prime target for cell-replacement and regenerative therapy. Triggering endogenous repair is a promising strategy to restore β-cell mass and normoglycemia in diabetic patients. Potential strategies include targeting specific β-cell subpopulations to increase proliferation or maturation. Alternatively, transdifferentiation of pancreatic islet cells (e.g. α- or δ-cells), extra-islet cells (acinar and ductal cells), hepatocytes, or intestinal cells into insulin-producing cells might improve glycemic control. To this end, it is crucial to systematically characterize and unravel the transcriptional program of all pancreatic cell types at the molecular level in homeostasis and disease. Furthermore, it is necessary to better determine the underlying mechanisms of β-cell maturation, maintenance, and dysfunction in diabetes, to identify and molecularly profile endocrine subpopulations with regenerative potential, and to translate the findings from mice to man. Recent approaches in single-cell biology started to illuminate heterogeneity and plasticity in the pancreas that might be targeted for β-cell regeneration in diabetic patients.

SCOPE OF REVIEW

This review discusses recent literature on single-cell analysis including single-cell RNA sequencing, single-cell mass cytometry, and flow cytometry of pancreatic cell types in the context of mechanisms of endogenous β-cell regeneration. We discuss new findings on the regulation of postnatal β-cell proliferation and maturation. We highlight how single-cell analysis recapitulates described principles of functional β-cell heterogeneity in animal models and adds new knowledge on the extent of β-cell heterogeneity in humans as well as its role in homeostasis and disease. Furthermore, we summarize the findings on cell subpopulations with regenerative potential that might enable the formation of new β-cells in diseased state. Finally, we review new data on the transcriptional program and function of rare pancreatic cell types and their implication in diabetes.

MAJOR CONCLUSION

Novel, single-cell technologies offer high molecular resolution of cellular heterogeneity within the pancreas and provide information on processes and factors that govern β-cell homeostasis, proliferation, and maturation. Eventually, these technologies might lead to the characterization of cells with regenerative potential and unravel disease-associated changes in gene expression to identify cellular and molecular targets for therapy.

Transplantation of human fetal pancreatic progenitor cells ameliorates renal injury in streptozotocin-induced diabetic nephropathy

Background

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Pancreas or islet transplantation has been reported to prevent the development of DN lesions and ameliorate or reverse existing glomerular lesions in animal models. Shortage of pancreas donor is a severe problem. Islets derived from stem cells may offer a potential solution to this problem.

Objective

To evaluate the effect of stem cell-derived islet transplantation on DN in a rat model of streptozotocin-induced DM.

Methods

Pancreatic progenitor cells were isolated from aborted fetuses of 8 weeks of gestation. And islets were prepared by suspension culture after a differentiation of progenitor cells in medium containing glucagon-like peptide-1 (Glp-1) and nicotinamide. Then islets were transplanted into the liver of diabetic rats via portal vein. Blood glucose, urinary volume, 24 h urinary protein and urinary albumin were measured once biweekly for 16 weeks. Graft survival was evaluated by monitoring human C-peptide level in rat sera and by immunohistochemical staining for human mitochondrial antigen and human C-peptide in liver tissue. The effect of progenitor-derived islets on filtration membrane was examined by electron microscopy and real-time polymerase chain reaction (PCR). Immunohistochemical staining, real-time PCR and western blot were employed for detecting fibronectin, protein kinase C beta (PKCβ), protein kinase A (PKA), inducible nitric oxide synthase (iNOS) and superoxide dismutase (SOD).

Results

Islet-like clusters derived from 8th gestational-week human fetal pancreatic progenitors survived in rat liver. And elevated serum level of human C-peptide was detected. Blood glucose, 24 h urinary protein and urinary albumin were lower in progenitor cell group than those in DN or insulin treatment group. Glomerular basement membrane thickness and fibronectin accumulation decreased significantly while podocytes improved morphologically in progenitor cell group. Furthermore, receptor of advanced glycation end products and PKCβ became down-regulated whereas PKA up-regulated by progenitor cell-derived islets. And iNOS rose while SOD declined.

Conclusions

DN may be reversed by transplantation of human fetal pancreatic progenitor cell-derived islets. And fetal pancreatic progenitor cells offer potential resources for cell replacement therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1253-1) contains supplementary material, which is available to authorized users.

Forkhead Protein FoxO1 Acts as a Repressor to Inhibit Cell Differentiation in Human Fetal Pancreatic Progenitor Cells

Our colleagues have reported previously that human pancreatic progenitor cells can readily differentiate into insulin-containing cells. Particularly, transplantation of these cell clusters upon in vitro induction for 3-4 w partially restores hyperglycemia in diabetic nude mice. In this study, we used human fetal pancreatic progenitor cells to identify the forkhead protein FoxO1 as the key regulator for cell differentiation. Thus, induction of human fetal pancreatic progenitor cells for 1 week led to increase of the pancreatic β cell markers such as Ngn3, but decrease of stem cell markers including Oct4, Nanog, and CK19. Of note, FoxO1 knockdown or FoxO1 inhibitor significantly upregulated Ngn3 and insulin as well as the markers such as Glut2, Kir6.2, SUR1, and VDCC, which are designated for mature β cells. On the contrary, overexpression of FoxO1 suppressed the induction and reduced expression of these β cell markers. Taken together, these results suggest that FoxO1 may act as a repressor to inhibit cell differentiation in human fetal pancreatic progenitor cells.

Insulin-Producing Cells Differentiated from Human Bone Marrow Mesenchymal Stem Cells In Vitro Ameliorate Streptozotocin-Induced Diabetic Hyperglycemia

BACKGROUND

The two major obstacles in the successful transplantation of islets for diabetes treatment are inadequate supply of insulin-producing tissue and immune rejection. Induction of the differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) into insulin-producing cells (IPCs) for autologous transplantation may alleviate those limitations.

METHODS

hMSCs were isolated and induced to differentiate into IPCs through a three-stage differentiation protocol in a defined media with high glucose, nicotinamide, and exendin-4. The physiological characteristics and functions of IPCs were then evaluated. Next, about 3 × 10(6) differentiated cells were transplanted into the renal sub-capsular space of streptozotocin (STZ)-induced diabetic nude mice. Graft survival and function were assessed by immunohistochemistry, TUNEL staining and measurements of blood glucose levels in the mice.

RESULTS

The differentiated IPCs were characterized by Dithizone (DTZ) positive staining, expression of pancreatic β-cell markers, and human insulin secretion in response to glucose stimulation. Moreover, 43% of the IPCs showed L-type Ca2+ channel activity and similar changes in intracellular Ca2+ in response to glucose stimulation as that seen in pancreatic β-cells in the process of glucose-stimulated insulin secretion. Transplantation of functional IPCs into the renal subcapsular space of STZ-induced diabetic nude mice ameliorated the hyperglycemia. Immunofluorescence staining revealed that transplanted IPCs sustainably expressed insulin, c-peptide, and PDX-1 without apparent apoptosis in vivo.

CONCLUSIONS

IPCs derived from hMSCs in vitro can ameliorate STZ-induced diabetic hyperglycemia, which indicates that these hMSCs may be a promising approach to overcome the limitations of islet transplantation.

Fetal Kidney Cells Can Ameliorate Ischemic Acute Renal Failure in Rats through Their Anti-Inflammatory, Anti-Apoptotic and Anti-Oxidative Effects

Fetal kidney cells may contain multiple populations of kidney stem cells and thus appear to be a suitable cellular therapy for the treatment of acute renal failure (ARF) but their biological characteristics and therapeutic potential have not been adequately explored. We have culture expanded fetal kidney cells derived from rat fetal kidneys, characterized them and evaluated their therapeutic effect in an ischemia reperfusion (IR) induced rat model of ARF. The fetal kidney cells grew in culture as adherent spindle shaped/polygonal cells and expressed CD29, CD44, CD73, CD90, CD105, CD24 and CD133 markers. Administration of PKH26 labeled fetal kidney cells in ARF rats resulted in a significant decrease in the levels of blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin and decreased tubular necrosis in the kidney tissues (p<0.05 for all). The injected fetal kidney cells were observed to engraft around injured tubular cells, and there was increased proliferation and decreased apoptosis of tubular cells in the kidneys (p<0.05 for both). In addition, the kidney tissues of ARF rats treated with fetal kidney cells had a higher gene expression of renotropic growth factors (VEGF-A, IGF-1, BMP-7 and bFGF) and anti-inflammatory cytokine (IL10); up regulation of anti-oxidative markers (HO-1 and NQO-1); and a lower Bax/Bcl2 ratio as compared to saline treated rats (p<0.05 for all). Our data shows that culture expanded fetal kidney cells express mesenchymal and renal progenitor markers, and ameliorate ischemic ARF predominantly by their anti-apoptotic, anti-inflammatory and anti-oxidative effects.

A cost-minimization analysis of tissue-engineered constructs for corneal endothelial transplantation

Corneal endothelial transplantation or endothelial keratoplasty has become the preferred choice of transplantation for patients with corneal blindness due to endothelial dysfunction. Currently, there is a worldwide shortage of transplantable tissue, and demand is expected to increase further with aging populations. Tissue-engineered alternatives are being developed, and are likely to be available soon. However, the cost of these constructs may impair their widespread use. A cost-minimization analysis comparing tissue-engineered constructs to donor tissue procured from eye banks for endothelial keratoplasty was performed. Both initial investment costs and recurring costs were considered in the analysis to arrive at a final tissue cost per transplant. The clinical outcomes of endothelial keratoplasty with tissue-engineered constructs and with donor tissue procured from eye banks were assumed to be equivalent. One-way and probabilistic sensitivity analyses were performed to simulate various possible scenarios, and to determine the robustness of the results. A tissue engineering strategy was cheaper in both investment cost and recurring cost. Tissue-engineered constructs for endothelial keratoplasty could be produced at a cost of US$880 per transplant. In contrast, utilizing donor tissue procured from eye banks for endothelial keratoplasty required US$3,710 per transplant. Sensitivity analyses performed further support the results of this cost-minimization analysis across a wide range of possible scenarios. The use of tissue-engineered constructs for endothelial keratoplasty could potentially increase the supply of transplantable tissue and bring the costs of corneal endothelial transplantation down, making this intervention accessible to a larger group of patients. Tissue-engineering strategies for corneal epithelial constructs or other tissue types, such as pancreatic islet cells, should also be subject to similar pharmacoeconomic analyses.

Human fetal pancreatic islet-like structures as source material to treat type 1 diabetes

The incidence of type 1 diabetes is increasing worldwide. Current therapy continues to be suboptimal. An exciting therapeutic advance in the short term is closed loop technology development and application. However, cell and tissue therapy continues to be an unmet need for the disorder. Human islets isolated from deceased donors will be clinically available to treat type 1 diabetes within the next 1 to 2 years. Other approaches such as xenotransplantation and islet products derived from human embryonic stem cells and induced pluripotent stem cells are currently being pursued. The current commentary provides context and discusses future endeavors for transplantation of islet-like structures derived from fetal pancreas.