Adult Murine Pancreatic Progenitors Require Epidermal Growth Factor and Nicotinamide for Self-Renewal and Differentiation in a Serum- and Conditioned Medium-Free Culture

Methylcellulose colony assay and single-cell micro-manipulation reveal progenitor-like cells in adult human pancreatic ducts

Progenitor cells capable of self-renewal and differentiation in the adult human pancreas are an under-explored resource for regenerative medicine. Using micro-manipulation and three-dimensional colony assays we identify cells within the adult human exocrine pancreas that resemble progenitor cells. Exocrine tissues were dissociated into single cells and plated into a colony assay containing methylcellulose and 5% Matrigel. A subpopulation of ductal cells formed colonies containing differentiated ductal, acinar, and endocrine lineage cells, and expanded up to 300-fold with a ROCK inhibitor. When transplanted into diabetic mice, colonies pre-treated with a NOTCH inhibitor gave rise to insulin-expressing cells. Both colonies and primary human ducts contained cells that simultaneously express progenitor transcription factors SOX9, NKX6.1, and PDX1. In addition, in silico analysis identified progenitor-like cells within ductal clusters in a single-cell RNA sequencing dataset. Therefore, progenitor-like cells capable of self-renewal and tri-lineage differentiation either pre-exist in the adult human exocrine pancreas, or readily adapt in culture.

A matrigel-free method for culture of pancreatic endocrine-like cells in defined protein-based hydrogels

The transplantation of pancreatic endocrine islet cells from cadaveric donors is a promising treatment for type 1 diabetes (T1D), which is a chronic autoimmune disease that affects approximately nine million people worldwide. However, the demand for donor islets outstrips supply. This problem could be solved by differentiating stem and progenitor cells to islet cells. However, many current culture methods used to coax stem and progenitor cells to differentiate into pancreatic endocrine islet cells require Matrigel, a matrix composed of many extracellular matrix (ECM) proteins secreted from a mouse sarcoma cell line. The undefined nature of Matrigel makes it difficult to determine which factors drive stem and progenitor cell differentiation and maturation. Additionally, it is difficult to control the mechanical properties of Matrigel without altering its chemical composition. To address these shortcomings of Matrigel, we engineered defined recombinant proteins roughly 41 kDa in size, which contain cell-binding ECM peptides derived from fibronectin (ELYAVTGRGDSPASSAPIA) or laminin alpha 3 (PPFLMLLKGSTR). The engineered proteins form hydrogels through association of terminal leucine zipper domains derived from rat cartilage oligomeric matrix protein. The zipper domains flank elastin-like polypeptides whose lower critical solution temperature (LCST) behavior enables protein purification through thermal cycling. Rheological measurements show that a 2% w/v gel of the engineered proteins display material behavior comparable to a Matrigel/methylcellulose-based culture system previously reported by our group to support the growth of pancreatic ductal progenitor cells. We tested whether our protein hydrogels in 3D culture could derive endocrine and endocrine progenitor cells from dissociated pancreatic cells of young (1-week-old) mice. We found that both protein hydrogels favored growth of endocrine and endocrine progenitor cells, in contrast to Matrigel-based culture. Because the protein hydrogels described here can be further tuned with respect to mechanical and chemical properties, they provide new tools for mechanistic study of endocrine cell differentiation and maturation.

Optimization of differentiation protocols of dental tissues stem cells to pancreatic β-cells

Background

Despite the recent progress in the differentiation strategies of stem cells into pancreatic beta cell lineage, current protocols are not optimized for different cell types. The purpose of this study is to investigate and compare the ability of stem cells derived from dental pulp (DPSCs) and periodontal ligament (PDLSCs) as two anatomically different dental tissues to differentiate into pancreatic beta cells while assessing the most suitable protocol for each cell type.

Methods

DPSCs & PDLSCs were isolated and characterized morphologically and phenotypically and then differentiated into pancreatic beta cells using two protocols. Differentiated cells were assessed by qRT-PCR for the expression of pancreatic related markers Foxa-2, Sox-17, PDX-1, Ngn-3, INS and Gcg. Functional assessment of differentiation was performed by quantification of Insulin release via ELISA.

Results

Protocol 2 implementing Geltrex significantly enhanced the expression levels of all tested genes both in DPSCs & PDLSCs. Both DPSCs & PDLSCs illustrated improved response to increased glucose concentration in comparison to undifferentiated cells. Moreover, DPSCs demonstrated an advanced potency towards pancreatic lineage differentiation over PDLSCs under both protocols.

Conclusion

In conclusion, the current study reports the promising potential of dental derived stem cells in differentiating into pancreatic lineage through selection of the right protocol.

Liver organoids: an in vitro 3D model for liver cancer study

Primary liver cancer (PLC) is the second leading cause of cancer mortality worldwide, and its morbidity unceasingly increases these years. Hepatitis B virus (HBV) infection accounted for approximately 50% of hepatocellular carcinoma (HCC) cases globally in 2015. Due to the lack of an effective model to study HBV-associated liver carcinogenesis, research has made slow progress. Organoid, an in vitro 3D model which maintains self-organization, has recently emerged as a powerful tool to investigate human diseases. In this review, we first summarize the categories and development of liver organoids. Then, we mainly focus on the functions of culture medium components and applications of organoids for HBV infection and HBV-associated liver cancer studies. Finally, we provide insights into a potential patient-derived organoid model from those infected with HBV based on our study, as well as the limitations and future applications of organoids in liver cancer research.

Living biobank-based cancer organoids: prospects and challenges in cancer research

Biobanks bridge the gap between basic and translational research. Traditional cancer biobanks typically contain normal and tumor tissues, and matched blood. However, biospecimens in traditional biobanks are usually nonrenewable. In recent years, increased interest has focused on establishing living biobanks, including organoid biobanks, for the collection and storage of viable and functional tissues for long periods of time. The organoid model is based on a 3D in vitro cell culture system, is highly similar to primary tissues and organs in vivo, and can recapitulate the phenotypic and genetic characteristics of target organs. Publications on cancer organoids have recently increased, and many types of cancer organoids have been used for modeling cancer processes, as well as for drug discovery and screening. On the basis of the current research status, more exploration of cancer organoids through technical advancements is required to improve reproducibility and scalability. Moreover, given the natural characteristics of organoids, greater attention must be paid to ethical considerations. Here, we summarize recent advances in cancer organoid biobanking research, encompassing rectal, gastric, pancreatic, breast, and glioblastoma cancers. Living cancer biobanks that contain cancerous tissues and matched organoids with different genetic backgrounds, subtypes, and individualized characteristics will eventually contribute to the understanding of cancer and ultimately facilitate the development of innovative treatments.

Pancreatic Organoids for Regenerative Medicine and Cancer Research

In recent years, the development of ex vivo organoid cultures has gained substantial attention as a model to study regenerative medicine and diseases in several tissues. Diabetes and pancreatic ductal adenocarcinoma (PDAC) are the two major devastating diseases affecting the pancreas. Suitable models for regenerative medicine in diabetes and to accurately study PDAC biology and treatment response are essential in the pancreatic field. Pancreatic organoids can be generated from healthy pancreas or pancreatic tumors and constitute an important translational bridge between in vitro and in vivo models. Here, we review the rapidly emerging field of pancreatic organoids and summarize the current applications of the technology to tissue regeneration, disease modelling, and drug screening.

A pancreas tumor derived organoid study: from drug screen to precision medicine

Pancreatic ductal adenocarcinoma (PDAC) one of the deadliest malignant tumor. Despite considerable progress in pancreatic cancer treatment in the past 10 years, PDAC mortality has shown no appreciable change, and systemic therapies for PDAC generally lack efficacy. Thus, developing biomarkers for treatment guidance is urgently required. This review focuses on pancreatic tumor organoids (PTOs), which can mimic the characteristics of the original tumor in vitro. As a powerful tool with several applications, PTOs represent a new strategy for targeted therapy in pancreatic cancer and contribute to the advancement of the field of personalized medicine.

Nicotinamide promotes pancreatic differentiation through the dual inhibition of CK1 and ROCK kinases in human embryonic stem cells

Background

Vitamin B3 (nicotinamide) plays important roles in metabolism as well as in SIRT and PARP pathways. It is also recently reported as a novel kinase inhibitor with multiple targets. Nicotinamide promotes pancreatic cell differentiation from human embryonic stem cells (hESCs). However, its molecular mechanism is still unclear. In order to understand the molecular mechanism involved in pancreatic cell fate determination, we analyzed the downstream pathways of nicotinamide in the derivation of NKX6.1⁺ pancreatic progenitors from hESCs.

Methods

We applied downstream modulators of nicotinamide during the induction from posterior foregut to pancreatic progenitors, including niacin, PARP inhibitor, SIRT inhibitor, CK1 inhibitor and ROCK inhibitor. The impact of those treatments was evaluated by quantitative real-time PCR, flow cytometry and immunostaining of pancreatic markers. Furthermore, CK1 isoforms were knocked down to validate CK1 function in the induction of pancreatic progenitors. Finally, RNA-seq was used to demonstrate pancreatic induction on the transcriptomic level.

Results

First, we demonstrated that nicotinamide promoted pancreatic progenitor differentiation in chemically defined conditions, but it did not act through either niacin-associated metabolism or the inhibition of PARP and SIRT pathways. In contrast, nicotinamide modulated differentiation through CK1 and ROCK inhibition. We demonstrated that CK1 inhibitors promoted the generation of PDX1/NKX6.1 double-positive pancreatic progenitor cells. shRNA knockdown revealed that the inhibition of CK1α and CK1ε promoted pancreatic progenitor differentiation. We then showed that nicotinamide also improved pancreatic progenitor differentiation through ROCK inhibition. Finally, RNA-seq data showed that CK1 and ROCK inhibition led to pancreatic gene expression, similar to nicotinamide treatment.

Conclusions

In this report, we revealed that nicotinamide promotes generation of pancreatic progenitors from hESCs through CK1 and ROCK inhibition. Furthermore, we discovered the novel role of CK1 in pancreatic cell fate determination.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02426-2.

Integrative protocols for an in vitro generation of pancreatic progenitors from human dental pulp stem cells

Efficiency of the induction protocol is crucial for the generation of insulin-producing cells (IPCs) from human dental pulp stem cells (hDPSCs). Here, we established the integrative induction protocol by merging genetic manipulation technique with our previous published 3-step induction protocol aiming to enhance the pancreatic progenitor commitment and production yield. We found that the overexpression of PDX1 following with 3-step induction protocol were able to generate the 3-dimensional (3D) colony structure of pancreatic progenitors (PPs) with the beneficial trends of pancreatic endoderm commitment and production yield, while other protocols using the prolong maintenance of PDX1-overexpressed hDPSCs and the PDX1 overexpression after definitive endoderm induction were unable to generate and sustain the 3D structure of the colonies. Further Notch signaling manipulation by DAPT treatment showed lesser degree of positive effects on progenitor commitment and production yield. Although the generated PPs from the integrative protocol expressed pancreatic mRNA markers along with pro-insulin and insulin proteins, they still contained the defective glucose-responsive C-peptide secretion. Only basal secreted C-peptide level was observed. In summary, the integrative induction protocol potentially enhanced the PP generation with high colony production yield and could serve as an efficient platform for further hDPSC-derived IPC production and maturation.

Organoids from the Human Fetal and Adult Pancreas

PURPOSE OF REVIEW

Novel 3D organoid culture techniques have enabled long-term expansion of pancreatic tissue. This review comprehensively summarizes and evaluates the applications of primary tissue-derived pancreatic organoids in regenerative studies, disease modelling, and personalized medicine.

RECENT FINDINGS

Organoids derived from human fetal and adult pancreatic tissue have been used to study pancreas development and repair. Generated adult human pancreatic organoids harbor the capacity for clonal expansion and endocrine cell formation. In addition, organoids have been generated from human pancreatic ductal adenocarcinoma in order to study tumor behavior and assess drug responses. Pancreatic organoids constitute an important translational bridge between in vitro and in vivo models, enhancing our understanding of pancreatic cell biology. Current applications for pancreatic organoid technology include studies on tissue regeneration, disease modelling, and drug screening.

A GLIS3-CD133-WNT-signaling axis regulates the self-renewal of adult murine pancreatic progenitor-like cells in colonies and organoids

The existence and regenerative potential of resident stem and progenitor cells in the adult pancreas are controversial topics. A question that has been only minimally addressed is the capacity of a progenitor cell to self-renew, a key attribute that defines stem cells. Previously, our laboratory has identified putative stem and progenitor cells from the adult murine pancreas. Using an ex vivo colony/organoid culture system, we demonstrated that these stem/progenitor-like cells have self-renewal and multilineage differentiation potential. We have named these cells pancreatic colony-forming units (PCFUs) because they can give rise to three-dimensional colonies. However, the molecular mechanisms by which PCFUs self-renew have remained largely unknown. Here, we tested the hypothesis that PCFU self-renewal requires GLIS family zinc finger 3 (GLIS3), a zinc-finger transcription factor important in pancreas development. Pancreata from 2- to 4-month-old mice were dissociated, sorted for CD133^highCD71^low ductal cells, known to be enriched for PCFUs, and virally transduced with shRNAs to knock down GLIS3 and other proteins. We then plated these cells into our colony assays and analyzed the resulting colonies for protein and gene expression. Our results revealed a previously unknown GLIS3-to-CD133-to-WNT signaling axis in which GLIS3 and CD133 act as factors necessary for maintaining WNT receptors and signaling molecules in colonies, allowing responses to WNT ligands. Additionally, we found that CD133, but not GLIS3 or WNT, is required for phosphoinositide 3-kinase (PI3K)/AKT Ser/Thr kinase (AKT)-mediated PCFU survival. Collectively, our results uncover a molecular pathway that maintains self-renewal of adult murine PCFUs.

Isolation and Characterization of Colony-Forming Progenitor Cells from Adult Pancreas

Obtaining, growing, and analysis of pancreatic progenitor cells. Adult stem and progenitor cells have been successfully used for cell-based therapies such as transplantation of hematopoietic stem cells for various diseases. Whether stem and progenitor cells in the adult pancreas can be identified and used for replacement therapy has been a highly controversial topic. To address this controversy, our laboratory has developed in vitro colony assays to detect and characterize individual pancreatic stem and progenitor-like cells. We found that a subpopulation of ductal cells in the adult murine pancreas has the abilities to self-renew and differentiate into multiple pancreatic lineages in three-dimensional space in methylcellulose-containing semisolid media. This protocol details the techniques used for culturing and characterizing these pancreatic stem and progenitor-like cells, which we have named pancreatic colony-forming units (PCFUs), as well as their progenies (colonies). The techniques presented here include dissociation of pancreases, sorting antibody-stained cells with a fluorescence-activated cell sorter, viral transduction of dissociated pancreatic cells, growth of PCFUs in semi-solid media, whole-mount immunostaining and Western blot analysis for proteins expressed in colonies, and kidney capsule transplantation of colonies for in vivo functional analysis.

Mutual inhibitions between epidermal growth factor receptor signaling and miR-124a control pancreatic progenitor proliferation

Pancreatic stem/progenitor cells convert from a proliferative to a differentiated fate passing through proliferation cease to a resting state. However, the molecular mechanisms of cell cycle arrest are poorly understood. In this study, we demonstrated that the microRNA-124a (miR-124a) inhibited the proliferation of pancreatic progenitor cells both in vitro and ex vivo and promoted a quiescent state. The miR-124a directly targeted SOS Ras/Rac guanine nucleotide exchange factor 1 (SOS1), IQ motif-containing GTPase-activating protein 1 (IQGAP1), signal transducer and activator of transcription 3 (STAT3), and cyclin D2 (CCND2), thereby inactivating epidermal growth factor receptor (EGFR) downstream signaling pathways including mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK), phosphatidylinositol 3-kinase-protein kinase B (PI3K/AKT) and Janus kinase (JAK)/STAT3. miR-124a blocked cell proliferation mainly through targeting STAT3 to inhibit PI3K/AKT and JAK/STAT3 signaling. Moreover, miR-124a expression was negatively regulated by EGFR downstream PI3K/AKT signaling. These results indicated that miR-124a and EGFR signaling mutually interact to form a regulating circuit that determines the proliferation of pancreatic progenitor cells.

Personalized epigenetic management of diabetes

The novel genome-wide assays of epigenetic marks have resulted in a greater understanding of how genetics and the environment interact in the development and inheritance of diabetes. Chronic hyperglycemia induces epigenetic changes in multiple organs, contributing to diabetic complications. Specific epigenetic-modifying compounds have been developed to erase these modifications, possibly slowing down the onset of diabetes-related complications. The current review is an update of the previously published paper, describing the most recent advances in the epigenetics of diabetes.