Systematically labeling developmental stage-specific genes for the study of pancreatic β-cell differentiation from human embryonic stem cells

Transplantation of chemically induced pluripotent stem-cell-derived islets under abdominal anterior rectus sheath in a type 1 diabetes patient

We report the 1-year results from one patient as the preliminary analysis of a first-in-human phase I clinical trial (ChiCTR2300072200) assessing the feasibility of autologous transplantation of chemically induced pluripotent stem-cell-derived islets (CiPSC islets) beneath the abdominal anterior rectus sheath for type 1 diabetes treatment. The patient achieved sustained insulin independence starting 75 days post-transplantation. The patient's time-in-target glycemic range increased from a baseline value of 43.18% to 96.21% by month 4 post-transplantation, accompanied by a decrease in glycated hemoglobin, an indicator of long-term systemic glucose levels at a non-diabetic level. Thereafter, the patient presented a state of stable glycemic control, with time-in-target glycemic range at >98% and glycated hemoglobin at around 5%. At 1 year, the clinical data met all study endpoints with no indication of transplant-related abnormalities. Promising results from this patient suggest that further clinical studies assessing CiPSC-islet transplantation in type 1 diabetes are warranted.

The dual role of SUSD2 in cancer development

Sushi domain-containing protein 2 (SUSD2, also known as the complement control protein domain) is a representative and vital protein in the SUSD protein family involved in many physiological and pathological processes beyond complement regulation. Cancer is one of the leading causes of death worldwide. The complex role of SUSD2 in tumorigenesis and cancer progression has raised increasing concerns. Studies suggest that SUSD2 has different regulatory tendencies among different tumors and exerts its biological effects in a cancer type-specific manner; for instance, it has oncogenic effects on breast cancer, gastric cancer, and glioma and has tumor-suppression effects on lung cancer, bladder cancer, and colon cancer. Moreover, SUSD2 can be regulated by noncoding RNAs, its promoter methylation and other molecules, such as Galectin-1 (Gal-1), tropomyosin alpha-4 chain (TPM4), and p63. The therapeutic implications of targeting SUSD2 have already been preliminarily revealed in some malignancies, including melanoma, colon cancer, and breast cancer. This article reviews the role and regulatory mechanisms of SUSD2 in cancer development, as well as its structure and distribution. We hope that this review will advance the understanding of SUSD2 as a diagnostic and/or prognostic biomarker and provide new avenues for the development of novel cancer therapies.

Anti-correlated feature selection prevents false discovery of subpopulations in scRNAseq

While sub-clustering cell-populations has become popular in single cell-omics, negative controls for this process are lacking. Popular feature-selection/clustering algorithms fail the null-dataset problem, allowing erroneous subdivisions of homogenous clusters until nearly each cell is called its own cluster. Using real and synthetic datasets, we find that anti-correlated gene selection reduces or eliminates erroneous subdivisions, increases marker-gene selection efficacy, and efficiently scales to millions of cells.

Inferring regulators of cell identity in the human adult pancreas

Cellular identity during development is under the control of transcription factors that form gene regulatory networks. However, the transcription factors and gene regulatory networks underlying cellular identity in the human adult pancreas remain largely unexplored. Here, we integrate multiple single-cell RNA-sequencing datasets of the human adult pancreas, totaling 7393 cells, and comprehensively reconstruct gene regulatory networks. We show that a network of 142 transcription factors forms distinct regulatory modules that characterize pancreatic cell types. We present evidence that our approach identifies regulators of cell identity and cell states in the human adult pancreas. We predict that HEYL, BHLHE41 and JUND are active in acinar, beta and alpha cells, respectively, and show that these proteins are present in the human adult pancreas as well as in human induced pluripotent stem cell (hiPSC)-derived islet cells. Using single-cell transcriptomics, we found that JUND represses beta cell genes in hiPSC-alpha cells. BHLHE41 depletion induced apoptosis in primary pancreatic islets. The comprehensive gene regulatory network atlas can be explored interactively online. We anticipate our analysis to be the starting point for a more sophisticated dissection of how transcription factors regulate cell identity and cell states in the human adult pancreas.

Single-cell transcriptome analysis of NEUROG3+ cells during pancreatic endocrine differentiation with small molecules

The efficiency of inducing human embryonic stem cells into NEUROG3+ pancreatic endocrine cells is a bottleneck in stem cell therapy for diabetes. To understand the cell properties and fate decisions during differentiation, we analyzed the modified induction method using single-cell transcriptome and found that DAPT combined with four factors (4FS): nicotinamide, dexamethasone, forskolin and Alk5 inhibitor II (DAPT + 4FS) increased the expression of NEUROG3 to approximately 34.3%. The increased NEUROG3+ cells were mainly concentrated in Insulin + Glucagon + (INS + GCG+) and SLAC18A1 + Chromogranin A+(SLAC18A1 + CHGA +) populations, indicating that the increased NEUROG3+ cells promoted the differentiation of pancreatic endocrine cells and enterochromaffin-like cells. Single-cell transcriptome analysis provided valuable clues for further screening of pancreatic endocrine cells and differentiation of pancreatic islet cells. The gene set enrichment analysis (GSEA) suggest that we can try to promote the expression of INS + GCG+ population by up-regulating G protein-coupled receptor (GPCR) and mitogen-activated protein kinase signals and down-regulating Wnt, NIK/NF-KappaB and cytokine-mediated signal pathways. We can also try to regulate GPCR signaling through PLCE1, so as to increase the proportion of NEUROG3+ cells in INS+GCG+ populations. To exclude non-pancreatic endocrine cells, ALCAM^high CD9^low could be used as a marker for endocrine populations, and ALCAM^high CD9^lowCDH1^low could remove the SLC18A1 + CHGA+ population.

Bariatric Surgery: Targeting pancreatic β cells to treat type II diabetes

Pancreatic β-cell function impairment and insulin resistance are central to the development of obesity-related type 2 diabetes mellitus (T2DM). Bariatric surgery (BS) is a practical treatment approach to treat morbid obesity and achieve lasting T2DM remission. Traditionally, sustained postoperative glycemic control was considered a direct result of decreased nutrient intake and weight loss. However, mounting evidence in recent years implicated a weight-independent mechanism that involves pancreatic islet reconstruction and improved β-cell function. In this article, we summarize the role of β-cell in the pathogenesis of T2DM, review recent research progress focusing on the impact of Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) on pancreatic β-cell pathophysiology, and finally discuss therapeutics that have the potential to assist in the treatment effect of surgery and prevent T2D relapse.

N-acetylcysteine regulates dental follicle stem cell osteogenesis and alveolar bone repair via ROS scavenging

Background

Dental follicle stem cells (DFSCs) show mesenchymal stem cell properties with the potential for alveolar bone regeneration. Stem cell properties can be impaired by reactive oxygen species (ROS), prompting us to examine the importance of scavenging ROS for stem cell-based tissue regeneration. This study aimed to investigate the effect and mechanism of N-acetylcysteine (NAC), a promising antioxidant, on the properties of DFSCs and DFSC-based alveolar bone regeneration.

Methods

DFSCs were cultured in media supplemented with different concentrations of NAC (0–10 mM). Cytologic experiments, RNA-sequencing and antioxidant assays were performed in vitro in human DFSCs (hDFSCs). Rat maxillary first molar extraction models were constructed, histological and radiological examinations were performed at day 7 post-surgery to investigate alveolar bone regeneration in tooth extraction sockets after local transplantation of NAC, rat DFSCs (rDFSCs) or NAC-treated rDFSCs.

Results

5 mM NAC-treated hDFSCs exhibited better proliferation, less senescent rate, higher stem cell-specific marker and immune-related factor expression with the strongest osteogenic differentiation; other concentrations were also beneficial for maintaining stem cell properties. RNA-sequencing identified 803 differentially expressed genes between hDFSCs with and without 5 mM NAC. “Developmental process (GO:0032502)” was prominent, bioinformatic analysis of 394 involved genes revealed functional and pathway enrichment of ossification and PI3K/AKT pathway, respectively. Furthermore, after NAC treatment, the reduction of ROS levels (ROS, superoxide, hydrogen peroxide), the induction of antioxidant levels (glutathione, catalase, superoxide dismutase), the upregulation of PI3K/AKT signaling (PI3K-p110, PI3K-p85, AKT, phosphorylated-PI3K-p85, phosphorylated-AKT) and the rebound of ROS level upon PI3K/AKT inhibition were showed. Local transplantation of NAC, rDFSCs or NAC-treated rDFSCs was safe and promoted oral socket bone formation after tooth extraction, with application of NAC-treated rDFSCs possessing the best effect.

Conclusions

The proper concentration of NAC enhances DFSC properties, especially osteogenesis, via PI3K/AKT/ROS signaling, and offers clinical potential for stem cell-based alveolar bone regeneration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03161-y.

Human pluripotent stem-cell-derived islets ameliorate diabetes in non-human primates

Human pluripotent stem-cell-derived islets (hPSC-islets) are a promising cell resource for diabetes treatment^1,2. However, this therapeutic strategy has not been systematically assessed in large animal models physiologically similar to humans, such as non-human primates³. In this study, we generated islets from human chemically induced pluripotent stem cells (hCiPSC-islets) and show that a one-dose intraportal infusion of hCiPSC-islets into diabetic non-human primates effectively restored endogenous insulin secretion and improved glycemic control. Fasting and average pre-prandial blood glucose levels significantly decreased in all recipients, accompanied by meal or glucose-responsive C-peptide release and overall increase in body weight. Notably, in the four long-term follow-up macaques, average hemoglobin A1c dropped by over 2% compared with peak values, whereas the average exogenous insulin requirement reduced by 49% 15 weeks after transplantation. Collectively, our findings show the feasibility of hPSC-islets for diabetic treatment in a preclinical context, marking a substantial step forward in clinical translation of hPSC-islets.

Chemical combinations potentiate human pluripotent stem cell-derived 3D pancreatic progenitor clusters toward functional β cells

Human pluripotent stem cell (hPSC)-derived pancreatic β cells are an attractive cell source for treating diabetes. However, current derivation methods remain inefficient, heterogeneous, and cell line dependent. To address these issues, we first devised a strategy to efficiently cluster hPSC-derived pancreatic progenitors into 3D structures. Through a systematic study, we discovered 10 chemicals that not only retain the pancreatic progenitors in 3D clusters but also enhance their potentiality towards NKX6.1+/INS+ β cells. We further systematically screened signaling pathway modulators in the three steps from pancreatic progenitors toward β cells. The implementation of all these strategies and chemical combinations resulted in generating β cells from different sources of hPSCs with high efficiency. The derived β cells are functional and can reverse hyperglycemia in mice within two weeks. Our protocol provides a robust platform for studying human β cells and developing hPSC-derived β cells for cell replacement therapy.

Purification of Live Stem-Cell-Derived Islet Lineage Intermediates

Stem-cell-derived tissues offer platforms to study organ development, model physiology during health and disease, and test novel therapies. We describe methods to isolate cells at successive stages during in vitro differentiation of human stem cells into the pancreatic endocrine lineage. Using flow cytometry, we purify live lineage intermediates in numbers not available by fetal biopsy. These include pancreatic and endocrine progenitors, isolated based on known surface markers. We further report a strategy that leverages intracellular zinc content and DPP4/CD26 expression to separate monohormonal insulin⁺ β cells from polyhormonal counterparts. These methods enable comprehensive molecular profiling during human islet lineage progression. © 2020 Wiley Periodicals LLC. Basic Protocol: In vitro isolation of human islet developmental intermediates.

CD82 is a marker to isolate β cell precursors from human iPS cells and plays a role for the maturation of β cells

Generation of pancreatic β cells from pluripotent stem cells is a key technology to develop cell therapy for insulin-dependent diabetes and considerable efforts have been made to produce β cells. However, due to multiple and lengthy differentiation steps, production of β cells is often unstable. It is also desirable to eliminate undifferentiated cells to avoid potential risks of tumorigenesis. To isolate β cell precursors from late stage pancreatic endocrine progenitor (EP) cells derived from iPS cells, we have identified CD82, a member of the tetraspanin family. CD82⁺ cells at the EP stage differentiated into endocrine cells more efficiently than CD82^- EP stage cells. We also show that CD82⁺ cells in human islets secreted insulin more efficiently than CD82^- cells. Furthermore, knockdown of CD82 expression by siRNA or inhibition of CD82 by monoclonal antibodies in NGN3⁺ cells suppressed the function of β cells with glucose-stimulated insulin secretion, suggesting that CD82 plays a role in maturation of EP cells to β cells.

Activating mutations of STAT3: Impact on human growth

The signal transducer and activator of transcription (STAT) 3 is the most ubiquitous member of the STAT family and fulfills fundamental functions in immune and non-immune cells. Mutations in the STAT3 gene lead to different human diseases. Germline STAT3 activating or gain-of-function (GOF) mutations result in early-onset multiorgan autoimmunity, lymphoproliferation, recurrent infections and short stature. Since the first description of the disease, the clinical manifestations of STAT3 GOF mutations have expanded considerably. However, due to the complexity of immunological characteristics in patients carrying STAT3 GOF mutations, most of attention was focused on the immune alterations. This review summarizes current knowledge on STAT3 GOF mutations with special focus on the growth defects, since short stature is a predominant feature in this condition. Underlying mechanisms of STAT3 GOF disease are still poorly understood, and potential effects of STAT3 GOF mutations on the growth hormone signaling pathway are unclear. Functional studies of STAT3 GOF mutations and the broadening of clinical growth-related data in these patients are necessary to better delineate implications of STAT3 GOF mutations on growth.

Optimization of Factor Combinations for Stem Cell Differentiations on a Design-of-Experiment Microfluidic Chip

Directed differentiation of stem cells plays a vital role in cell replacement therapy. Many activators and inhibitors targeting different signaling pathways have been identified to contribute to each step of differentiation. Most studies relied on empirically optimizing the combinations of the aforementioned factors for each step to optimize the efficiency of differentiation, which are time-consuming and nonsystematic. Design-of-experiment (DOE) is a powerful strategy to identify the critical combinations from multiple factors systematically. However, it is prohibitively complicated for typical laboratories, given a large number of potential combinations. Here, we develop a multilayer polymethyl methacrylate-based, reusable microfluidic chip to directly facilitate the DOE in the differentiation of stem cells. The chip consists of an inlet layer and multiple disperse layers. Different solutions are injected simultaneously to the chip through the inlet layer. Subsequently, the channels in the disperse layers split and recombine the flow streams to generate solution combinations based on hard-wired DOE designs. We demonstrated that it is in quantitative agreement with the designs using fluorescent dyes. Moreover, we constructed a human-induced pluripotent stem reporter cell line to improve the consistency of the cellular state measurements and use the chip to identify critical factors for cell differentiation to definitive endoderm (DE). We found that the differentiation efficiencies under various factor combinations are significantly different, and CHIR99201 and GDF8 are the most critical factors for differentiation to DE. Our method is potentially applicable to the optimization of factor combinations for multi-step stem cell differentiation and combinatorial drug screening.

Human T Cells Expressing a CD19 CAR-T Receptor Provide Insights into Mechanisms of Human CD19-Positive β Cell Destruction

Autoimmune destruction of pancreatic β cells underlies type 1 diabetes (T1D). To understand T cell-mediated immune effects on human pancreatic β cells, we combine β cell-specific expression of a model antigen, CD19, and anti-CD19 chimeric antigen receptor T (CAR-T) cells. Coculturing CD19-expressing β-like cells and CD19 CAR-T cells results in T cell-mediated β-like cell death with release of activated T cell cytokines. Transcriptome analysis of β-like cells and human islets treated with conditioned medium of the immune reaction identifies upregulation of immune reaction genes and the pyroptosis mediator GSDMD as well as its activator CASP4. Caspase-4-mediated cleaved GSDMD is detected in β-like cells under inflammation and endoplasmic reticulum (ER) stress conditions. Among immune-regulatory genes, PDL1 is one of the most upregulated, and PDL1 overexpression partially protects human β-like cells transplanted into mice. This experimental platform identifies potential mechanisms of β cell destruction and may allow testing of therapeutic strategies.

CD19-expressing β-like cells differentiated from human ES cells are functional

Tractable in vitro and in vivo killing of CD19-expressing β-like cells by CAR-T cells

Upregulation of pyroptosis factors GSDMD and CAPS4 during β-like cell inflammation

PDL1-overexpressing in β-like cells partially protects against reactive T cells

Transient FOXO1 inhibition in pancreatic endoderm promotes the generation of NGN3+ endocrine precursors from human iPSCs

In the multi-step differentiation protocol used to generate pancreatic endocrine cells from human pluripotent stem cells, the induction of NGN3+ endocrine precursors from the PDX1+/NKX6.1+ pancreatic endoderm is crucial for efficient endocrine cell production. Here, we demonstrate that transient, not prolonged FOXO1 inhibition results in enhanced NGN3+ endocrine precursors and hormone-producing cell production. FOXO1 inhibition does not directly induce NGN3 expression but stimulates PDX1+/NKX6.1+ cell proliferation. NOTCH activity, whose suppression is important for Ngn3 expression, is not suppressed but Wnt signaling is stimulated by FOXO1 inhibition. Reversely, Wnt inhibition suppresses the effects of FOXO1 inhibitor. These findings indicate that FOXO1 and Wnt are involved in regulating the proliferation of PDX1+/NKX6.1+ pancreatic endoderm that gives rise to NGN3+ endocrine precursors.

Reversible expansion of pancreatic islet progenitors derived from human induced pluripotent stem cells

Transplantation of pancreatic islets is an effective therapy for severe type 1 diabetes. As donor shortage is a major problem for this therapy, attempts have been made to produce a large number of pancreatic islets from human pluripotent stem cells (hPSCs). However, as the differentiation of hPSCs to pancreatic islets requires multiple and lengthy processes using various expensive cytokines, the process is variable, low efficiency and costly. Therefore, it would be beneficial if islet progenitors could be expanded. Neurogenin3 (NGN3)-expressing pancreatic endocrine progenitor (EP) cells derived from hPSCs exhibited the ability to differentiate into pancreatic islets while their cell cycle was arrested. By using a lentivirus vector, we introduced several growth-promoting genes into NGN3-expressing EP cells. We found that SV40LT expression induced proliferation of the EP cells but reduced the expression of endocrine lineage-commitment factors, NGN3, NEUROD1 and NKX2.2, resulting in the suppression of islet differentiation. By using the Cre-loxP system, we removed SV40LT after the expansion, leading to re-expression of endocrine-lineage commitment genes and differentiation into functional pancreatic islets. Thus, our findings will pave a way to generate a large quantity of functional pancreatic islets through the expansion of EP cells from hPSCs.

Circadian Entrainment Triggers Maturation of Human In Vitro Islets

Stem-cell-derived tissues could transform disease research and therapy, yet most methods generate functionally immature products. We investigate how human pluripotent stem cells (hPSCs) differentiate into pancreatic islets in vitro by profiling DNA methylation, chromatin accessibility, and histone modification changes. We find that enhancer potential is reset upon lineage commitment and show how pervasive epigenetic priming steers endocrine cell fates. Modeling islet differentiation and maturation regulatory circuits reveals genes critical for generating endocrine cells and identifies circadian control as limiting for in vitro islet function. Entrainment to circadian feeding/fasting cycles triggers islet metabolic maturation by inducing cyclic synthesis of energy metabolism and insulin secretion effectors, including antiphasic insulin and glucagon pulses. Following entrainment, hPSC-derived islets gain persistent chromatin changes and rhythmic insulin responses with a raised glucose threshold, a hallmark of functional maturity, and function within days of transplantation. Thus, hPSC-derived tissues are amenable to functional improvement by circadian modulation.

Development of a Human Photoacoustic Imaging Reporter Gene Using the Clinical Dye Indocyanine Green

Purpose

To develop a photoacoustic imaging (PAI) reporter gene that has high translational potential. Previous research has shown that human organic anion-transporting polypeptide 1b3 (OATP1B3) promotes the uptake of the near-infrared fluorescent dye indocyanine green (ICG). In this study, the authors have established OATP1B3 and ICG as a reporter gene-probe pair for in vivo PAI.

Materials and Methods

Human breast cancer cells were engineered to express OATP1B3. Control cells (not expressing OATP1B3) or OATP1B3-expressing cells were incubated with or without ICG, placed in a breast-mimicking phantom, and imaged with PAI. Control (n = 6) or OATP1B3-expressing (n = 5) cells were then implanted orthotopically into female mice. Full-spectrum PAI was performed before and 24 hours after ICG administration. One-way analysis of variance was performed, followed by Tukey posthoc multiple comparisons, to assess statistical significance.

Results

OATP1B3-expressing cells incubated with ICG exhibited a 2.7-fold increase in contrast-to-noise ratio relative to all other controls in vitro (P < .05). In mice, PAI signals after ICG administration were increased 2.3-fold in OATP1B3 tumors relative to those in controls (P < .05).

Conclusion

OATP1B3 operates as an in vivo PAI reporter gene based on its ability to promote the cellular uptake of ICG. Benefits include the human derivation of OATP1B3, combined with the use of wavelengths in the near-infrared region, high extinction coefficient, low quantum yield, and clinical approval of ICG. The authors posit that this system will be useful for localized monitoring of emerging gene- and cell-based therapies in clinical applications.© RSNA, 2019Keywords: Animal Studies, Molecular Imaging, Molecular Imaging-Clinical Translation, Molecular Imaging-Reporter Gene Imaging, Optical ImagingSupplemental material is available for this article.

Pluripotent Stem Cell-Derived Pancreatic Progenitors and β-Like Cells for Type 1 Diabetes Treatment

In this review, we focus on the processes guiding human pancreas development and provide an update on methods to efficiently generate pancreatic progenitors (PPs) and β-like cells in vitro from human pluripotent stem cells (hPSCs). Furthermore, we assess the strengths and weaknesses of using PPs and β-like cell for cell replacement therapy for the treatment of Type 1 diabetes with respect to cell manufacturing, engrafting, functionality, and safety. Finally, we discuss the identification and use of specific cell surface markers to generate safer populations of PPs for clinical translation and to study the development of PPs in vivo and in vitro.

Endocrine lineage biases arise in temporally distinct endocrine progenitors during pancreatic morphogenesis

Decoding the molecular composition of individual Ngn3 + endocrine progenitors (EPs) during pancreatic morphogenesis could provide insight into the mechanisms regulating hormonal cell fate. Here, we identify population markers and extensive cellular diversity including four EP subtypes reflecting EP maturation using high-resolution single-cell RNA-sequencing of the e14.5 and e16.5 mouse pancreas. While e14.5 and e16.5 EPs are constantly born and share select genes, these EPs are overall transcriptionally distinct concomitant with changes in the underlying epithelium. As a consequence, e16.5 EPs are not the same as e14.5 EPs: e16.5 EPs have a higher propensity to form beta cells. Analysis of e14.5 and e16.5 EP chromatin states reveals temporal shifts, with enrichment of beta cell motifs in accessible regions at later stages. Finally, we provide transcriptional maps outlining the route progenitors take as they make cell fate decisions, which can be applied to advance the in vitro generation of beta cells.

Endocrine progenitors form early in pancreatic development but the diversity of this cell population is unclear. Here, the authors use single cell RNA sequencing of the mouse pancreas at e14.5 and e16.5 to show that endocrine progenitors are temporally distinct and those formed later are more likely to become beta cells

Understanding human fetal pancreas development using subpopulation sorting, RNA sequencing and single-cell profiling

To decipher the populations of cells present in the human fetal pancreas and their lineage relationships, we developed strategies to isolate pancreatic progenitors, endocrine progenitors and endocrine cells. Transcriptome analysis of the individual populations revealed a large degree of conservation among vertebrates in the drivers of gene expression changes that occur at different steps of differentiation, although notably, sometimes, different members of the same gene family are expressed. The transcriptome analysis establishes a resource to identify novel genes and pathways involved in human pancreas development. Single-cell profiling further captured intermediate stages of differentiation and enabled us to decipher the sequence of transcriptional events occurring during human endocrine differentiation. Furthermore, we evaluate how well individual pancreatic cells derived in vitro from human pluripotent stem cells mirror the natural process occurring in human fetuses. This comparison uncovers a few differences at the progenitor steps, a convergence at the steps of endocrine induction, and the current inability to fully resolve endocrine cell subtypes in vitro.

Generation of carbamoyl phosphate synthetase 1 reporter cell lines for the assessment of ammonia metabolism

Both primary hepatocytes and stem cells-derived hepatocyte-like cells (HLCs) are major sources for bioartificial liver (BAL). Maintenance of hepatocellular functions and induction of functional maturity of HLCs are critical for BAL's support effect. It remains difficult to assess and improve detoxification functions inherent to hepatocytes, including ammonia clearance. Here, we aim to assess ammonia metabolism and identify ammonia detoxification enhancer by developing an imaging strategy. In hepatoma cell line HepG2, and immortalized hepatic cell line LO2, carbamoyl phosphate synthetase 1 (CPS1) gene, the first enzyme of ammonia-eliminating urea cycle, was labelled with fluorescence protein via CRISPR/Cas9 system. With the reporter-based screening approach, cellular detoxification enhancers were selected among a collection of 182 small molecules. In both CPS1 reporter cell lines, the fluorescence intensity is positively correlated with cellular CPS1 mRNA expression, ammonia elimination and secreted urea, and reflected ammonia detoxification in a dose-dependent manner. Surprisingly, high-level CPS1 reporter clones also reserved many other critical hepatocellular functions, for example albumin secretion and cytochrome 450 metabolic functions. Sodium phenylbutyrate and resveratrol were identified to enhance metabolism-related gene expression and liver-enriched transcription factors C/EBPα, HNF4α. In conclusion, the CPS1-reporter system provides an economic and effective platform for assessment of cellular metabolic function and high-throughput identification of chemical compounds that improve detoxification activities in hepatic lineage cells.

ZEB1 confers stem cell-like properties in breast cancer by targeting neurogenin-3

Cancer stem cells (CSCs) are a subpopulation of cancer cells believed to be implicated in cancer initiation, progression, and recurrence. Here, we report that ectopic expression of zinc finger E-box binding homeobox 1 protein (ZEB1) results in the acquisition of CSC properties by breast cancer cells, leading to tumor initiation and progression in vitro and in vivo. The neurogenin 3 gene (Ngn3) is a bona fide target of ZEB1, and its repression is a key factor contributing to ZEB1-induced cancer cell stemness. ZEB1 suppressed Ngn3 transcription by forming a ZEB1/DNA methyltransferase (DNMT)3B/histone deacetylase 1 (HDAC1) complex on the Ngn3 promoter, leading to promoter hypermethylation and gene silencing. The rescue of Ngn3 expression attenuated ZEB1-induced cancer stemness and symmetric CSC division. Immunohistological analysis of human breast cancer specimens revealed a strong inverse relationship between ZEB1 and NGN3 protein expression. Thus, our findings suggest ZEB1-mediated silencing of Ngn3 is required for breast tumor initiation and maintenance. Targeted therapies against the ZEB1/Ngn3 axis may be highly valuable for the prevention and treatment of breast cancer.

Reconstructing human pancreatic differentiation by mapping specific cell populations during development

Information remains scarce on human development compared to animal models. Here, we reconstructed human fetal pancreatic differentiation using cell surface markers. We demonstrate that at 7weeks of development, the glycoprotein 2 (GP2) marks a multipotent cell population that will differentiate into the acinar, ductal or endocrine lineages. Development towards the acinar lineage is paralleled by an increase in GP2 expression. Conversely, a subset of the GP2⁺ population undergoes endocrine differentiation by down-regulating GP2 and CD142 and turning on NEUROG3, a marker of endocrine differentiation. Endocrine maturation progresses by up-regulating SUSD2 and lowering ECAD levels. Finally, in vitro differentiation of pancreatic endocrine cells derived from human pluripotent stem cells mimics key in vivo events. Our work paves the way to extend our understanding of the origin of mature human pancreatic cell types and how such lineage decisions are regulated.

DOI:http://dx.doi.org/10.7554/eLife.27564.001

The quest to make fully functional human pancreatic beta cells from embryonic stem cells: climbing a mountain in the clouds

The production of fully functional insulin-secreting cells to treat diabetes is a major goal of regenerative medicine. In this article, I review progress towards this goal over the last 15 years from the perspective of a beta cell biologist. I describe the current state-of-the-art, and speculate on the general approaches that will be required to identify and achieve our ultimate goal of producing functional beta cells. The need for deeper phenotyping of heterogeneous cultures of stem cell derived islet-like cells in parallel with a better understanding of the heterogeneity of the target cell type(s) is emphasised. This deep phenotyping should include high-throughput single-cell analysis, as well as comprehensive 'omics technologies to provide unbiased characterisation of cell products and human beta cells. There are justified calls for more detailed and well-powered studies of primary human pancreatic beta cell physiology, and I propose online databases of standardised human beta cell responses to physiological stimuli, including both functional and metabolomic/proteomic/transcriptomic profiles. With a concerted, community-wide effort, including both basic and applied scientists, beta cell replacement will become a clinical reality for patients with diabetes.

Genome-edited human stem cell-derived beta cells: a powerful tool for drilling down on type 2 diabetes GWAS biology

Type 2 diabetes (T2D) is a disease of pandemic proportions, one defined by a complex aetiological mix of genetic, epigenetic, environmental, and lifestyle risk factors. Whilst the last decade of T2D genetic research has identified more than 100 loci showing strong statistical association with disease susceptibility, our inability to capitalise upon these signals reflects, in part, a lack of appropriate human cell models for study. This review discusses the impact of two complementary, state-of-the-art technologies on T2D genetic research: the generation of stem cell-derived, endocrine pancreas-lineage cells and the editing of their genomes. Such models facilitate investigation of diabetes-associated genomic perturbations in a physiologically representative cell context and allow the role of both developmental and adult islet dysfunction in T2D pathogenesis to be investigated. Accordingly, we interrogate the role that patient-derived induced pluripotent stem cell models are playing in understanding cellular dysfunction in monogenic diabetes, and how site-specific nucleases such as the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system are helping to confirm genes crucial to human endocrine pancreas development. We also highlight the novel biology gleaned in the absence of patient lines, including an ability to model the whole phenotypic spectrum of diabetes phenotypes occurring both in utero and in adult cells, interrogating the non-coding 'islet regulome' for disease-causing perturbations, and understanding the role of other islet cell types in aberrant glycaemia. This article aims to reinforce the importance of investigating T2D signals in cell models reflecting appropriate species, genomic context, developmental time point, and tissue type.

Progenitor cell niches in the human pancreatic duct system and associated pancreatic duct glands: an anatomical and immunophenotyping study

Pancreatic duct glands (PDGs) are tubule-alveolar glands associated with the pancreatic duct system and can be considered the anatomical counterpart of peribiliary glands (PBGs) found within the biliary tree. Recently, we demonstrated that endodermal precursor niches exist fetally and postnatally and are composed functionally of stem cells and progenitors within PBGs and of committed progenitors within PDGs. Here we have characterized more extensively the anatomy of human PDGs as novel niches containing cells with multiple phenotypes of committed progenitors. Human pancreata (n = 15) were obtained from cadaveric adult donors. Specimens were processed for histology, immunohistochemistry and immunofluorescence. PDGs were found in the walls of larger pancreatic ducts (diameters > 300 μm) and constituted nearly 4% of the duct wall area. All of the cells identified were negative for nuclear expression of Oct4, a pluripotency gene, and so are presumably committed progenitors and not stem cells. In the main pancreatic duct and in large interlobular ducts, Sox9(+) cells represented 5-30% of the cells within PDGs and were located primarily at the bottom of PDGs, whereas rare and scattered Sox9(+) cells were present within the surface epithelium. The expression of PCNA, a marker of cell proliferation, paralleled the distribution of Sox9 expression. Sox9(+) PDG cells proved to be Pdx1(+) /Ngn3(+/-) /Oct4A(-) . Nearly 10% of PDG cells were positive for insulin or glucagon. Intercalated ducts contained Sox9(+) /Pdx1(+) /Ngn3(+) cells, a phenotype that is presumptive of committed endocrine progenitors. Some intercalated ducts appeared in continuity with clusters of insulin-positive cells organized in small pancreatic islet-like structures. In summary, PDGs represent niches of a population of Sox9(+) cells exhibiting a pattern of phenotypic traits implicating a radial axis of maturation from the bottoms of the PDGs to the surface of pancreatic ducts. Our results complete the anatomical background that links biliary and pancreatic tracts and could have important implications for the common patho-physiology of biliary tract and pancreas.

Using stem cells to produce insulin

INTRODUCTION

Tremendous progress has been made in generating insulin-producing cells from pluripotent stem cells. The best outcome of the refined protocols became apparent in the first clinical trial announced by ViaCyte, based on the implantation of pancreatic progenitors that would further mature into functional insulin-producing cells inside the patient's body.

AREAS COVERED

Several groups, including ours, have contributed to improve strategies to generate insulin-producing cells. Of note, the latest results have gained a substantial amount of interest as a method to create a potentially functional and limitless supply of β-cell to revert diabetes mellitus. This review analyzes the accomplishments that have taken place over the last few decades, summarizes the state-of-art methods for β-cell replacement therapies based on the differentiation of embryonic stem cells into glucose-responsive and insulin-producing cells in a dish and discusses alternative approaches to obtain new sources of insulin-producing cells.

EXPERT OPINION

Undoubtedly, recent events preface the beginning of a new era in diabetes therapy. However, in our opinion, a number of significant hurdles still stand in the way of clinical application. We believe that the combination of the private and public sectors will accelerate the process of obtaining the desired safe and functional β-cell surrogates.

KeyGenes, a Tool to Probe Tissue Differentiation Using a Human Fetal Transcriptional Atlas

Differentiated derivatives of human pluripotent stem cells in culture are generally phenotypically immature compared to their adult counterparts. Their identity is often difficult to determine with certainty because little is known about their human fetal equivalents in vivo. Cellular identity and signaling pathways directing differentiation are usually determined by extrapolating information from either human adult tissue or model organisms, assuming conservation with humans. To resolve this, we generated a collection of human fetal transcriptional profiles at different developmental stages. Moreover, we developed an algorithm, KeyGenes, which uses this dataset to quantify the extent to which next-generation sequencing or microarray data resemble specific cell or tissue types in the human fetus. Using KeyGenes combined with the human fetal atlas, we identified multiple cell and tissue samples unambiguously on a limited set of features. We thus provide a flexible and expandable platform to monitor and evaluate the efficiency of differentiation in vitro.

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NGS-derived transcriptional profiles of human fetal tissues/organs are generated

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Algorithm called KeyGenes uses a training set to predict the identity of a test set

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KeyGenes using the fetal atlas identifies NGS- and microarray-derived data

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KeyGenes is a flexible and expandable platform to monitor stem cell differentiations

Controlled induction of human pancreatic progenitors produces functional beta-like cells in vitro

Directed differentiation of human pluripotent stem cells into functional insulin-producing beta-like cells holds great promise for cell replacement therapy for patients suffering from diabetes. This approach also offers the unique opportunity to study otherwise inaccessible aspects of human beta cell development and function in vitro. Here, we show that current pancreatic progenitor differentiation protocols promote precocious endocrine commitment, ultimately resulting in the generation of non-functional polyhormonal cells. Omission of commonly used BMP inhibitors during pancreatic specification prevents precocious endocrine formation while treatment with retinoic acid followed by combined EGF/KGF efficiently generates both PDX1(+) and subsequent PDX1(+)/NKX6.1(+) pancreatic progenitor populations, respectively. Precise temporal activation of endocrine differentiation in PDX1(+)/NKX6.1(+) progenitors produces glucose-responsive beta-like cells in vitro that exhibit key features of bona fide human beta cells, remain functional after short-term transplantation, and reduce blood glucose levels in diabetic mice. Thus, our simplified and scalable system accurately recapitulates key steps of human pancreas development and provides a fast and reproducible supply of functional human beta-like cells.