Inhibition of Hes1 activity in gall bladder epithelial cells promotes insulin expression and glucose responsiveness

Biochemical pancreatic β-cell lineage reprogramming: Various cell fate shifts

The incidence of pancreatic diseases has been continuously rising in recent years. Thus, research on pancreatic regeneration is becoming more popular. Chronic hyperglycemia is detrimental to pancreatic β-cells, leading to impairment of insulin secretion which is the main hallmark of pancreatic diseases. Obtaining plenty of functional pancreatic β-cells is the most crucial aspect when studying pancreatic biology and treating diabetes. According to the International Diabetes Federation, diabetes has become a global epidemic, with about 3 million people suffering from diabetes worldwide. Hyperglycemia can lead to many dangerous diseases, including amputation, blindness, neuropathy, stroke, and cardiovascular and kidney diseases. Insulin is widely used in the treatment of diabetes; however, innovative approaches are needed in the academic and preclinical stages. A new approach aims at synthesizing patient-specific functional pancreatic β-cells. The present article focuses on how cells from different tissues can be transformed into pancreatic β-cells.

Pancreas patch grafting to treat type 1 diabetes

Stem/progenitor cell therapy is a promising treatment option for patients with type 1 diabetes (T1D) a disease characterized by autoimmune destruction of pancreatic β cells. Actively injecting cells into an organ is one option for cell delivery, but in the pancreas, this contributes to acute inflammation and pancreatitis. We employed a patch grafting approach to transplant biliary tree stem cells/progenitor cells (BTSC) onto the surface of the pancreas in diabetic mice. The cells engraft and differentiate into β-like cells reversing hyperglycemia during a four-month period of observation. In addition, C-peptide and insulin gradually increase in blood circulation without detectable adverse effects during this period. Moreover, the patch graft transplant promoted the proliferation and differentiation of pancreatic β-like cells with co-expression of the β cell biomarker. CONCLUSION: BTSC transplantation can effectively attenuate T1D over a four-month period that is vital important for clinical applications.

A Pro-Endocrine Pancreatic Islet Transcriptional Program Established During Development Is Retained in Human Gallbladder Epithelial Cells

BACKGROUND & AIMS

Pancreatic islet β-cells are factories for insulin production; however, ectopic expression of insulin also is well recognized. The gallbladder is a next-door neighbor to the developing pancreas. Here, we wanted to understand if gallbladders contain functional insulin-producing cells.

METHODS

We compared developing and adult mouse as well as human gallbladder epithelial cells and islets using immunohistochemistry, flow cytometry, enzyme-linked immunosorbent assays, RNA sequencing, real-time polymerase chain reaction, chromatin immunoprecipitation, and functional studies.

RESULTS

We show that the epithelial lining of developing, as well as adult, mouse and human gallbladders naturally contain interspersed cells that retain the capacity to actively transcribe, translate, package, and release insulin. We show that human gallbladders also contain functional insulin-secreting cells with the potential to naturally respond to glucose in vitro and in situ. Notably, in a non-obese diabetic (NOD) mouse model of type 1 diabetes, we observed that insulin-producing cells in the gallbladder are not targeted by autoimmune cells. Interestingly, in human gallbladders, insulin splice variants are absent, although insulin splice forms are observed in human islets.

CONCLUSIONS

In summary, our biochemical, transcriptomic, and functional data in mouse and human gallbladder epithelial cells collectively show the evolutionary and developmental similarities between gallbladder and the pancreas that allow gallbladder epithelial cells to continue insulin production in adult life. Understanding the mechanisms regulating insulin transcription and translation in gallbladder epithelial cells would help guide future studies in type 1 diabetes therapy.

Targeting β-cell dedifferentiation and transdifferentiation: opportunities and challenges

The most distinctive pathological characteristics of diabetes mellitus induced by various stressors or immune-mediated injuries are reductions of pancreatic islet β-cell populations and activity. Existing treatment strategies cannot slow disease progression; consequently, research to genetically engineer β-cell mimetics through bi-directional plasticity is ongoing. The current consensus implicates β-cell dedifferentiation as the primary etiology of reduced β-cell mass and activity. This review aims to summarize the etiology and proposed mechanisms of β-cell dedifferentiation and to explore the possibility that there might be a time interval from the onset of β-cell dysfunction caused by dedifferentiation to the development of diabetes, which may offer a therapeutic window to reduce β-cell injury and to stabilize functionality. In addition, to investigate β-cell plasticity, we review strategies for β-cell regeneration utilizing genetic programming, small molecules, cytokines, and bioengineering to transdifferentiate other cell types into β-cells; the development of biomimetic acellular constructs to generate fully functional β-cell-mimetics. However, the maturation of regenerated β-cells is currently limited. Further studies are needed to develop simple and efficient reprogramming methods for assembling perfectly functional β-cells. Future investigations are necessary to transform diabetes into a potentially curable disease.

Regenerative medicine and cell-based approaches to restore pancreatic function

The pancreas is a complex organ with exocrine and endocrine components. Many pathologies impair exocrine function, including chronic pancreatitis, cystic fibrosis and pancreatic ductal adenocarcinoma. Conversely, when the endocrine pancreas fails to secrete sufficient insulin, patients develop diabetes mellitus. Pathology in either the endocrine or exocrine pancreas results in devastating economic and personal consequences. The current standard therapy for treating patients with type 1 diabetes mellitus is daily exogenous insulin injections, but cell sources of insulin provide superior glycaemic regulation and research is now focused on the goal of regenerating or replacing β cells. Stem-cell-based models might be useful to study exocrine pancreatic disorders, and mesenchymal stem cells or secreted factors might delay disease progression. Although the standards that bioengineered cells must meet before being considered as a viable therapy are not yet established, any potential therapy must be acceptably safe and functionally superior to current therapies. Here, we describe progress and challenges in cell-based methods to restore pancreatic function, with a focus on optimizing the site for cell delivery and decreasing requirements for immunosuppression through encapsulation. We also discuss the tools and strategies being used to generate exocrine pancreas and insulin-producing β-cell surrogates in situ and highlight obstacles to clinical application.

Reprogramming human gallbladder cells into insulin-producing β-like cells

The gallbladder and cystic duct (GBCs) are parts of the extrahepatic biliary tree and share a common developmental origin with the ventral pancreas. Here, we report on the very first genetic reprogramming of patient-derived human GBCs to β-like cells for potential autologous cell replacement therapy for type 1 diabetes. We developed a robust method for large-scale expansion of human GBCs ex vivo. GBCs were reprogrammed into insulin-producing pancreatic β-like cells by a combined adenoviral-mediated expression of hallmark pancreatic endocrine transcription factors PDX1, MAFA, NEUROG3, and PAX6 and differentiation culture in vitro. The reprogrammed GBCs (rGBCs) strongly induced the production of insulin and pancreatic endocrine genes and these responded to glucose stimulation in vitro. rGBCs also expressed an islet-specific surface marker, which was used to enrich for the most highly reprogrammed cells. More importantly, global mRNA and microRNA expression profiles and protein immunostaining indicated that rGBCs adopted an overall β-like state and these rGBCs engrafted in immunodeficient mice. Furthermore, comparative global expression analyses identified putative regulators of human biliary to β cell fate conversion. In summary, we have developed, for the first time, a reliable and robust genetic reprogramming and culture expansion of primary human GBCs—derived from multiple unrelated donors—into pancreatic β-like cells ex vivo, thus showing that human gallbladder is a potentially rich source of reprogrammable cells for autologous cell therapy in diabetes.

Lineage Reprogramming: A Promising Road for Pancreatic β Cell Regeneration

Cell replacement therapy is a promising method to restore pancreatic β cell function and cure diabetes. Distantly related cells (fibroblasts, keratinocytes, and muscle cells) and developmentally related cells (hepatocytes, gastrointestinal, and pancreatic exocrine cells) have been successfully reprogrammed into β cells in vitro and in vivo. However, while some reprogrammed β cells bear similarities to bona fide β cells, others do not develop into fully functional β cells. Here we review various strategies currently used for β cell reprogramming, including ectopic expression of specific transcription factors associated with islet development, repression of maintenance factors of host cells, regulation of epigenetic modifications, and microenvironmental changes. Development of simple and efficient reprogramming methods is a key priority for developing fully functional β cells suitable for cell replacement therapy.

Novel surface markers directed against adult human gallbladder

Novel cell surface-reactive monoclonal antibodies generated against extrahepatic biliary cells were developed for the isolation and characterization of different cell subsets from normal adult human gallbladder. Eleven antigenically distinct gallbladder subpopulations were isolated by fluorescence-activated cell sorting. They were classified into epithelial, mesenchymal, and pancreatobiliary (PDX1(+)SOX9(+)) subsets based on gene expression profiling. These antigenically distinct human gallbladder cell subsets could potentially also reflect different functional properties in regards to bile physiology, cell renewal and plasticity. Three of the novel monoclonal antibodies differentially labeled archival sections of primary carcinoma of human gallbladder relative to normal tissue. The novel monoclonal antibodies described herein enable the identification and characterization of antigenically diverse cell subsets within adult human gallbladder and are putative tumor biomarkers.

Generation of islet-like cells from mouse gall bladder by direct ex vivo reprogramming

Cell replacement is an emerging therapy for type 1 diabetes. Pluripotent stem cells have received a lot of attention as a potential source of transplantable β-cells, but their ability to form teratomas poses significant risks. Here, we evaluated the potential of primary mouse gall bladder epithelial cells (GBCs) as targets for ex vivo genetic reprogramming to the β-cell fate. Conditions for robust expansion and genetic transduction of primary GBCs by adenoviral vectors were developed. Using a GFP reporter for insulin, conditions for reprogramming were then optimized. Global expression analysis by RNA-sequencing was used to quantitatively compare reprogrammed GBCs (rGBCs) to true β-cells, revealing both similarities and differences. Adenoviral-mediated expression of NEUROG3, Pdx1, and MafA in GBCs resulted in robust induction of pancreatic endocrine genes, including Ins1, Ins2, Neurod1, Nkx2-2 and Isl1. Furthermore, expression of GBC-specific genes was repressed, including Sox17 and Hes1. Reprogramming was also enhanced by addition of retinoic acid and inhibition of Notch signaling. Importantly, rGBCs were able to engraft long term in vivo and remained insulin-positive for 15weeks. We conclude that GBCs are a viable source for autologous cell replacement in diabetes, but that complete reprogramming will require further manipulations.

Icariin potentiates the antitumor activity of gemcitabine in gallbladder cancer by suppressing NF-κB

AIM

Gemcitabine has been increasingly prescribed for the treatment of gallbladder cancer. However, the response rate is low. The aim of this study is to determine whether icariin, a flavonoid isolated from Epimedi herba, could potentiate the antitumor activity of gemcitabine in gallbladder cancer.

METHODS

Human gallbladder carcinoma cell lines GBC-SD and SGC-996 were tested. Cell proliferation and apoptosis were analyzed using MTT assay and flow cytometry, respectively. The expression of apoptosis- and proliferation-related molecules was detected with Western blotting. Caspase-3 activity was analyzed using colorimetric assay, and NF-κB activity was measured with ELISA. A gallbladder cancer xenograft model was established in female BALB/c (nu/nu) mice. The mice were intraperitoneally administered gemcitabine (125 mg/kg) in combination with icariin (40 mg/kg) for 2 weeks.

RESULTS

Icariin (40-160 μg/mL) dose-dependently suppressed cell proliferation and induced apoptosis in both GBC-SD and SGC-996 cells, with SGC-996 cells being less sensitive to the drug. Icariin (40 μg/mL) significantly enhanced the antitumor activity of gemcitabine (0.5 μmol/L) in both GBC-SD and SGC-996 cells. The mice bearing gallbladder cancer xenograft treated with gemcitabine in combination with icariin exhibited significantly smaller tumor size than the mice treated with either drug alone. In GBC-SD cells, icariin significantly inhibited both the constitutive and gemcitabine-induced NF-κB activity, enhanced caspase-3 activity, induced G(0)-G(1) phase arrest, and suppressed the expression of Bcl-2, Bcl-xL and surviving proteins.

CONCLUSION

Icariin, by suppressing NF-κB activity, exerts antitumor activity, and potentiates the antitumor activity of gemcitabine in gallbladder cancer. Combined administration of gemcitabine and icariin may offer a better therapeutic option for the patients with gallbladder cancer.

Hilar cholangiocarcinoma and pancreatic ductal adenocarcinoma share similar histopathologies, immunophenotypes, and development-related molecules

Embryologically, intrahepatic small bile ducts arise from hepatic progenitor cells via ductal plates, whereas the pancreato-extrahepatic biliary progenitor cells expressing the transcription factors PDX1 and HES1 are reportedly involved in the development of the extrahepatic biliary tract and ventral pancreas. The expression of cellular markers characteristic of the different anatomical levels of the biliary tree and pancreas, as well as PDX1 and HES1, was examined in cholangiocarcinoma components of combined hepatocellular cholangiocarcinoma (12 cases), intrahepatic cholangiocarcinoma (21 cases), hilar cholangiocarcinoma (25 cases), and pancreatic ductal adenocarcinoma (18 cases). Anterior gradient protein-2 and S100P were frequently expressed in hilar cholangiocarcinoma and pancreatic ductal adenocarcinoma, whereas neural cell adhesion molecule and luminal expression of epithelial membrane antigen were common in cholangiocarcinoma components of combined hepatocellular cholangiocarcinoma. PDX1 and HES1 were frequently and markedly expressed in pancreatic ductal adenocarcinoma and, to a lesser degree, in hilar cholangiocarcinoma, although their expression was rare and mild in cholangiocarcinoma components in combined hepatocellular cholangiocarcinoma. The expression patterns of these molecules in intrahepatic cholangiocarcinoma were intermediate between those in hilar cholangiocarcinoma and cholangiocarcinoma components of combined hepatocellular cholangiocarcinoma. Pancreatic ductal adenocarcinoma and hilar cholangiocarcinoma had a similar expression of mucin, immunophenotypes, as well as transcription factors. Pancreatic ductal adenocarcinoma and hilar cholangiocarcinoma showed similar postoperative prognosis. In conclusion, the similar expression of phenotypes related to pancreatobiliary anatomy and embryology may in part explain why these 2 types of carcinoma present similar clinicopathologic features. Further studies on the carcinogenesis of these carcinomas based on their similarities are warranted.

Progress in understanding the relationship of microRNAs with pancreas development and stem cell differentiation

MicroRNAs (miRNAs), a class of non-coding small RNAs involved in post-transcriptional gene regulation, play important roles in embryonic development, cell fate determination, and growth regulation. It has been shown that miRNAs contribute to the embryonic pancreas development by regulating several important transcriptional factors. Stem cells can be induced to differentiate into insulin-producing cells in vitro by mimicking the development of pancreatic β cells in vivo. MiRNAs may have regulatory roles in the maintenance and differentiation of stem cells. Therefore, elucidation of the mechanisms by which miRNAs regulate pancreas development and stem cell differentiation will provide novel insights into the development of therapeutic approach for diabetes.