Pancreas regeneration

RASEF/Rab45 regulates the formation and sorting of zymogen granules and secretion of digestive enzymes by pancreatic acinar cells

The pancreas is a glandular organ with both endocrine and exocrine functions. Researchers have investigated the roles of several Rab proteins, which are major regulators of membrane trafficking, in pancreatic exocytosis of zymogen granules in exocrine cells, also known as acinar cells. However, detailed molecular mechanisms mediated by Rab proteins are not fully understood. RASEF/Rab45 is an atypical Rab GTPase that contains N-terminal EF-hand and coiled-coil domains, as well as a C-terminal Rab-GTPase domain. In this study, we investigated the in vivo role of RASEF in pancreatic acinar cells using RASEF-knockout (KO) mice. Morphological analyses revealed that pancreatic acinar cells in RASEF-KO mice had an increased number of zymogen granules and abnormal formations of organelles, such as the endoplasmic reticulum (ER) and lysosomes. Biochemical analyses showed that ER proteins were decreased, but digestive enzymes were increased in the RASEF-KO pancreas. Moreover, trypsinogen was activated and co-localized with the endo-lysosomal marker LAMP1 in RASEF-KO pancreas. Upon cerulein administration to induce acute pancreatitis, impaired enzyme release from the pancreas was observed in the serum of RASEF-KO mice. These findings suggest that RASEF likely regulates the formation and sorting of zymogen granules and secretion of digestive enzymes by pancreatic acinar cells.

The effects of caffeine on pancreatic diseases: the known and possible mechanisms

Caffeine, a controversial substance, was once known to be addictive and harmful. In recent years, new effects of caffeine on the human body have been confirmed. Recent research over the past few decades has shown the potential of caffeine in treating pancreas-related diseases. This review aims to analyze the known and possible mechanisms of caffeine on pancreatic diseases and provides an overview of the current research status regarding the correlation between caffeine and pancreatic disease, while enhancing our understanding of their relationship.

Hollow Microfiber Assembly-Based Endocrine Pancreas-on-a-Chip for Sugar Substitute Evaluation

With the increasing demand for low-sugar, low-calorie healthy diets, artificial sweeteners are widely used as substitutes for sugar in the food industry. Therefore, developing models that can better predict the effects of sugar substitutes on the human body is necessary. Here, a new type of endocrine pancreas-on-a-chip is developed based on a microfiber assembly and its stimulation of pancreatic secretion by glucose or sugar substitutes is evaluated. This new endocrine pancreas-on-a-chip is assembled using two components: (1) a cell-loaded hollow methacrylate gelatin (GelMA)/calcium alginate (CaA) composite microfiber prepared by microfluidic spinning to achieve vascular simulation and material transport, and (2) a 3D pancreatic islet culture layer, which also serves as a fiber assembly microchip. Using this established organ chip, the effects of five sweeteners (glucose, erythritol, xylitol, sodium cyclamate, and sucralose) were investigated on pancreatic islet cell viability and insulin and glucagon secretion. The constructed endocrine pancreas-on-a-chip has potential for the safety evaluation of sugar-substituted food additives, which can expand the application of organ chips in the field of food safety and provide a new platform for evaluating various food additives.

Targeting β-Cell Plasticity: A Promising Approach for Diabetes Treatment

The β-cells within the pancreas play a pivotal role in insulin production and secretion, responding to fluctuations in blood glucose levels. However, factors like obesity, dietary habits, and prolonged insulin resistance can compromise β-cell function, contributing to the development of Type 2 Diabetes (T2D). A critical aspect of this dysfunction involves β-cell dedifferentiation and transdifferentiation, wherein these cells lose their specialized characteristics and adopt different identities, notably transitioning towards progenitor or other pancreatic cell types like α-cells. This process significantly contributes to β-cell malfunction and the progression of T2D, often surpassing the impact of outright β-cell loss. Alterations in the expressions of specific genes and transcription factors unique to β-cells, along with epigenetic modifications and environmental factors such as inflammation, oxidative stress, and mitochondrial dysfunction, underpin the occurrence of β-cell dedifferentiation and the onset of T2D. Recent research underscores the potential therapeutic value for targeting β-cell dedifferentiation to manage T2D effectively. In this review, we aim to dissect the intricate mechanisms governing β-cell dedifferentiation and explore the therapeutic avenues stemming from these insights.

Development, regeneration, and physiological expansion of functional β-cells: Cellular sources and regulators

Pancreatic regeneration is a complex process observed in both normal and pathological conditions. The aim of this review is to provide a comprehensive understanding of the emergence of a functionally active population of insulin-secreting β-cells in the adult pancreas. The renewal of β-cells is governed by a multifaceted interaction between cellular sources of genetic and epigenetic factors. Understanding the development and heterogeneity of β-cell populations is crucial for functional β-cell regeneration. The functional mass of pancreatic β-cells increases in situations such as pregnancy and obesity. However, the specific markers of mature β-cell populations and postnatal pancreatic progenitors capable of increasing self-reproduction in these conditions remain to be elucidated. The capacity to regenerate the β-cell population through various pathways, including the proliferation of pre-existing β-cells, β-cell neogenesis, differentiation of β-cells from a population of progenitor cells, and transdifferentiation of non-β-cells into β-cells, reveals crucial molecular mechanisms for identifying cellular sources and inducers of functional cell renewal. This provides an opportunity to identify specific cellular sources and mechanisms of regeneration, which could have clinical applications in treating various pathologies, including in vitro cell-based technologies, and deepen our understanding of regeneration in different physiological conditions.

Diverse associations between pancreatic intra-, inter-lobular fat and the development of type 2 diabetes in overweight or obese patients

Pancreatic fat is associated with obesity and type 2 diabetes mellitus (T2DM); however, the relationship between different types of pancreatic fat and diabetes status remains unclear. Therefore, we aimed to determine the potential of different types of pancreatic fat accumulation as a risk factor for T2DM in overweight or obese patients. In total, 104 overweight or obese patients were recruited from January 2020 to December 2022. The patients were divided into three groups: normal glucose tolerance (NGT), impaired fasting glucose or glucose tolerance (IFG/IGT), and T2DM. mDixon magnetic resonance imaging (MRI) was used to detect pancreatic fat in all three groups of patients. The pancreatic head fat (PHF), body fat (PBF), and tail fat (PTF) in the IFG/IGT group were 21, 20, and 31% more than those in the NGT group, respectively. PHF, PBF, and PTF were positively associated with glucose metabolic dysfunction markers in the NGT group, and inter-lobular fat volume (IFV) was positively associated with these markers in the IFG/IGT group. The areas under the receiver operating characteristic curves for PHF, PBF, and PTF (used to evaluate their diagnostic potential for glucose metabolic dysfunction) were 0.73, 0.73, and 0.78, respectively, while those for total pancreatic volume (TPV), pancreatic parenchymal volume, IFV, and IFV/TPV were 0.67, 0.67, 0.66, and 0.66, respectively. These results indicate that intra-lobular pancreatic fat, including PHF, PTF, and PBF, may be a potential independent risk factor for the development of T2DM. Additionally, IFV exacerbates glucose metabolic dysfunction. Intra-lobular pancreatic fat indices were better than IFV for the diagnosis of glucose metabolic dysfunction.

3D model of mouse embryonic pancreas and endocrine compartment using stem cell-derived mesoderm and pancreatic progenitors

The developing mouse pancreas is surrounded by mesoderm compartments providing signals that induce pancreas formation. Most pancreatic organoid protocols lack this mesoderm niche and only partially capture the pancreatic cell repertoire. This work aims to generate pancreatic aggregates by differentiating mouse embryonic stem cells (mESCs) into mesoderm progenitors (MPs) and pancreas progenitors (PPs), without using Matrigel. First, mESCs were differentiated into epiblast stem cells (EpiSCs) to enhance the PP differentiation rate. Next, PPs and MPs aggregated together giving rise to various pancreatic cell types, including endocrine, acinar, and ductal cells, and to endothelial cells. Single-cell RNA sequencing analysis revealed a larger endocrine population within the PP + MP aggregates, as compared to PPs alone or PPs in Matrigel aggregates. The PP + MP aggregate gene expression signatures and its endocrine population percentage closely resembled those of the endocrine population found in the mouse embryonic pancreas, which holds promise for studying pancreas development.

Co-exposure to PVC microplastics and cadmium induces oxidative stress and fibrosis in duck pancreas

PVC microplastics (PVC-MPs) are environmental pollutants that interact with cadmium (Cd) to exert various biological effects. Ducks belong to the waterfowl family of birds and therefore are at a higher risk of exposure to PVC-MPs and Cd than other animals. However, the effects of co-exposure of ducks to Cd and PVC-MPs are poorly understood. Here, we used Muscovy ducks to establish an in vivo model to explore the effects of co-exposure to 1 mg/L PVC-MPs and 50 mg/kg Cd on duck pancreas. After 2 months of treatment with 50 mg/kg Cd, pancreas weight decreased by 21 %, and the content of amylase and lipase increased by 25 % and 233 %. However, exposure to PVC-MPs did not significantly affect the pancreas. Moreover, co-exposure to PVC-MPs and Cd worsened the reduction of pancreas weight and disruption of pancreas function compared to exposure to either substance alone. Furthermore, our research has revealed that exposure to PVC-MPs or Cd disrupted mitochondrial structure, reduced ATP levels by 10 % and 18 %, inhibited antioxidant enzyme activity, and increased malondialdehyde levels by 153.8 % and 232.5 %. It was found that exposure to either PVC-MPs or Cd can induce inflammation and fibrosis in the duck pancreas. Notably, co-exposure to PVC-MPs and Cd exacerbated inflammation and fibrosis, with the content of IL-1, IL-6, and TNF-α increasing by 169 %, 199 %, and 98 %, compared to Cd exposure alone. The study emphasizes the significance of comprehending the potential hazards linked to exposure to these substances. In conclusion, it presents promising preliminary evidence that PVC-MPs accumulate in duck pancreas, and increase the accumulation of Cd. Co-exposure to PVC-MPs and Cd disrupts the structure and function of mitochondria and promotes the development of pancreas inflammation and fibrosis.

Among Other Tissues, Short-Term Garlic Oral Treatment Incrementally Improves Indicants of Only Pancreatic Islets of Langerhans Histology and Insulin mRNA Transcription and Synthesis in Diabetic Rats

BACKGROUND

The source, mRNA transcription, and synthesis of insulin in the pancreas, in addition to the bile duct and liver, in streptozotocin (STZ)-induced diabetic rats (DR) in response to garlic oral treatment are not yet clear.

OBJECTIVE

This study investigated the accumulative effects of continued garlic oral treatment on changes in the pancreas, bile duct, and liver with regards to: 1-Insulin mRNA transcription, synthesis, and concentration in relation to changes in serum insulin (SI); 2-Insulinogenic cells insulin intensity and distribution, proliferation, and morphology.

METHOD

Fasting blood glucose (FBG) and insulin concentration in serum and pancreas (PI) and sources and mRNA transcription in the pancreas, bile duct, and liver in normal rats given normal saline (NR-NS) and DR given either NS (DR-NS) or garlic extract (DR-GE) before and after 1, 4, and 8 weeks of oral treatment were examined.

RESULTS

Compared to NR-NS, DR-NS showed a significant increase in FBG and reductions in SI and PI and deterioration in islets histology, associated pancreatic insulin numerical intensities, and mRNA transcription. However, compared to DR-NS, the targeted biochemical, histological, and genetic variables of DR-GE were significantly and incrementally improved as garlic treatment continued. Insulin or its indicators were not detected either in the bile duct or the liver in DR-GE.

CONCLUSIONS

8 weeks of garlic oral treatment is enough to incrementally restore only pancreatic islets of Langerhans insulin intensity and insulinogenic cells proliferation, morphology, and distribution. These indices were associated with enhanced pancreatic insulin mRNA transcription and synthesis. Eight weeks of garlic treatment were not enough to stimulate insulinogenesis in either the bile duct or the liver.

The Integrated Stress Response in Pancreatic Development, Tissue Homeostasis, and Cancer

Present in all eukaryotic cells, the integrated stress response (ISR) is a highly coordinated signaling network that controls cellular behavior, metabolism, and survival in response to diverse stresses. The ISR is initiated when any 1 of 3 stress-sensing kinases (protein kinase R-like endoplasmic reticulum kinase [PERK], general control non-derepressible 2 [GCN2], double-stranded RNA-dependent protein kinase [PKR], heme-regulated eukaryotic translation initiation factor 2α kinase [HRI]) becomes activated to phosphorylate the protein translation initiation factor eukaryotic translation initiation factor 2α (eIF2α), shifting gene expression toward a comprehensive rewiring of cellular machinery to promote adaptation. Although the ISR has been shown to play an important role in the homeostasis of multiple tissues, evidence suggests that it is particularly crucial for the development and ongoing health of the pancreas. Among the most synthetically dynamic tissues in the body, the exocrine and endocrine pancreas relies heavily on the ISR to rapidly adjust cell function to meet the metabolic demands of the organism. The hardwiring of the ISR into normal pancreatic functions and adaptation to stress may explain why it is a commonly used pro-oncogenic and therapy-resistance mechanism in pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors. Here we review what is known about the key roles that the ISR plays in the development, homeostasis, and neoplasia of the pancreas.

Harnessing beta cell regeneration biology for diabetes therapy

The pandemic scale of diabetes mellitus is alarming, its complications remain devastating, and current treatments still pose a major burden on those affected and on the healthcare system as a whole. As the disease emanates from the destruction or dysfunction of insulin-producing pancreatic β-cells, a real cure requires their restoration and protection. An attractive strategy is to regenerate β-cells directly within the pancreas; however, while several approaches for β-cell regeneration have been proposed in the past, clinical translation has proven challenging. This review scrutinizes recent findings in β-cell regeneration and discusses their potential clinical implementation. Hereby, we aim to delineate a path for innovative, targeted therapies to help shift from 'caring for' to 'curing' diabetes.

LINC MIR503HG Controls SC-β Cell Differentiation and Insulin Production by Targeting CDH1 and HES1

Stem cell-derived pancreatic progenitors (SC-PPs), as an unlimited source of SC-derived β (SC-β) cells, offers a robust tool for diabetes treatment in stem cell-based transplantation, disease modeling, and drug screening. Whereas, PDX1+/NKX6.1+ PPs enhances the subsequent endocrine lineage specification and gives rise to glucose-responsive SC-β cells in vivo and in vitro. To identify the regulators that promote induction efficiency and cellular function maturation, single-cell RNA-sequencing is performed to decipher the transcriptional landscape during PPs differentiation. The comprehensive evaluation of functionality demonstrated that manipulating LINC MIR503HG using CRISPR in PP cell fate decision can improve insulin synthesis and secretion in mature SC-β cells, without effects on liver lineage specification. Importantly, transplantation of MIR503HG-/- SC-β cells in recipients significantly restored blood glucose homeostasis, accompanied by serum C-peptide release and an increase in body weight. Mechanistically, by releasing CtBP1 occupying the CDH1 and HES1 promoters, the decrease in MIR503HG expression levels provided an excellent extracellular niche and appropriate Notch signaling activation for PPs following differentiation. Furthermore, this exhibited higher crucial transcription factors and mature epithelial markers in CDH1High expressed clusters. Altogether, these findings highlighted MIR503HG as an essential and exclusive PP cell fate specification regulator with promising therapeutic potential for patients with diabetes.

Repressing miR-23a promotes the transdifferentiation of pancreatic α cells to β cells via negatively regulating the expression of SDF-1α

Pancreatic β-cell failure is a pathological feature in type 1 diabetes. One promising approach involves inducing transdifferentiation of related pancreatic cell types, specifically α cells that produce glucagon. The chemokine stromal cell-derived factor-1 alpha (SDF-1α) is implicated in pancreatic α-to-β like cell transition. Here, the serum level of SDF-1α was lower in T1D with C-peptide loss, the miR-23a was negatively correlated with SDF-1α. We discovered that exosomal miR-23a, secreted from β cells, functionally downregulates the expression of SDF-1α, leading to increased Pax4 expression and decreased Arx expression in vivo. Adenovirus-vectored miR-23a sponge and mimic were constructed to further explored the miR-23a on pancreatic α-to-β like cell transition in vitro, which yielded results consistent with our cell-based assays. Suppression of miR-23a upregulated insulin level and downregulated glucagon level in STZ-induced diabetes mice models, effectively promoting α-to-β like cell transition. Our findings highlight miR-23a as a new therapeutic target for regenerating pancreatic β cells from α cells.

Glucagon-producing α-cell transcriptional identity and reprogramming towards insulin production

β-Cell replacement by in situ reprogramming of non-β-cells is a promising diabetes therapy. Following the observation that near-total β-cell ablation in adult mice triggers the reprogramming of pancreatic α-, δ-, and γ-cells into insulin (INS)-producing cells, recent studies are delving deep into the mechanisms controlling adult α-cell identity. Systematic analyses of the α-cell transcriptome and epigenome have started to pinpoint features that could be crucial for maintaining α-cell identity. Using different transgenic and chemical approaches, significant advances have been made in reprogramming α-cells in vivo into INS-secreting cells in mice. The recent reprogramming of human α-cells in vitro is an important step forward that must now be complemented with a comprehensive molecular dissection of the mechanisms controlling α-cell identity.

Genetic lineage tracing identifies adaptive mechanisms of pancreatic islet β cells in various mouse models of diabetes with distinct age of initiation

During the pathogenesis of type 1 diabetes (T1D) and type 2 diabetes (T2D), pancreatic islets, especially the β cells, face significant challenges. These insulin-producing cells adopt a regeneration strategy to compensate for the shortage of insulin, but the exact mechanism needs to be defined. High-fat diet (HFD) and streptozotocin (STZ) treatment are well-established models to study islet damage in T2D and T1D respectively. Therefore, we applied these two diabetic mouse models, triggered at different ages, to pursue the cell fate transition of islet β cells. Cre-LoxP systems were used to generate islet cell type-specific (α, β, or δ) green fluorescent protein (GFP)-labeled mice for genetic lineage tracing, thereinto β-cell GFP-labeled mice were tamoxifen induced. Single-cell RNA sequencing (scRNA-seq) was used to investigate the evolutionary trajectories and molecular mechanisms of the GFP-labeled β cells in STZ-treated mice. STZ-induced diabetes caused extensive dedifferentiation of β cells and some of which transdifferentiated into a or δ cells in both youth- and adulthood-initiated mice while this phenomenon was barely observed in HFD models. β cells in HFD mice were expanded via self-replication rather than via transdifferentiation from α or δ cells, in contrast, α or δ cells were induced to transdifferentiate into β cells in STZ-treated mice (both youth- and adulthood-initiated). In addition to the re-dedifferentiation of β cells, it is also highly likely that these "α or δ" cells transdifferentiated from pre-existing β cells could also re-trans-differentiate into insulin-producing β cells and be beneficial to islet recovery. The analysis of ScRNA-seq revealed that several pathways including mitochondrial function, chromatin modification, and remodeling are crucial in the dynamic transition of β cells. Our findings shed light on how islet β cells overcome the deficit of insulin and the molecular mechanism of islet recovery in T1D and T2D pathogenesis.

Mettl3-Mediated m6A Methylation Controls Pancreatic Bipotent Progenitor Fate and Islet Formation

The important role of m6A RNA modification in β-cell function has been established; however, how it regulates pancreatic development and endocrine differentiation remains unknown. Here, we generated transgenic mice lacking RNA methyltransferase-like 3 (Mettl3) specifically in Pdx1+ pancreatic progenitor cells and found the mice with the mutation developed hyperglycemia and hypoinsulinemia at age 2 weeks, along with an atrophic pancreas, reduced islet mass, and abnormal increase in ductal formation. At embryonic day 15.5, Mettl3 deletion had caused a significant loss of Ngn3+ endocrine progenitor cells, which was accompanied by increased Sox9+ ductal precursor cells. We identified histone deacetylase 1 (Hdac1) as the critical direct m6A target in bipotent progenitors, the degeneration of which caused abnormal activation of the Wnt/Notch signaling pathway and blocked endocrine differentiation. This transformation could be manipulated in embryonic pancreatic culture in vitro through regulation of the Mettl3-Hdac1-Wnt/Notch signaling axis. Our finding that Mettl3 determines endocrine lineage by modulating Hdac1 activity during the transition of bipotent progenitors might help in the development of targeted endocrine cell protocols for diabetes treatment.

ARTICLE HIGHLIGHTS

Silencing hsa_circ_0032449 inhibits the pancreatic differentiation of human embryonic stem cells via the hsa_miR-195-5p/CCND1/PI3K/AKT signaling pathway

Stem cell-derived β cells (SC-β cells) differentiated from stem cell-derived pancreatic progenitor (PP) cells are promising tools for enabling normal glucose control of islet transplants and have therapeutic potential for type 1 diabetes treatment. Pancreatic specification is essential for SC-β cell induction in vitro and low-quality PP cells may convert into derivatives of non-pancreatic lineages both in vivo and in vitro, impeding PP-derived β cell safety and differentiation efficiency. Circular RNA (circRNA) commonly determines the fate of stem cells by acting as competing endogenous RNA (ceRNA). Currently, the relationships between endogenous circRNA and pancreatic specification remain elusive. Herein, we used whole transcriptome sequencing analysis and functional experiments to reveal that deficiency of hsa_circ_0032449 resulted in posterior foregut-derived PP cells with a weakened the progenitor state with decreased expression of PDX1, NKX6.1 and CCND1. As differentiation processed into maturation, silencing of hsa_circ_0032449 suppressed PP cell development into functionally mature and glucose-responsive SC-β cells. These SC-β cells exhibited lower serum C-peptide levels compared with those of control groups in nude mice and had difficulties in reversing hyperglycemia in STZ-induced diabetic nude mice. Mechanistically, loss of hsa_circ_0032449 participated in PI3K-AKT signaling transduction by acting as a ceRNA to sponge miR-195-5p and by influencing the expression of the downstream target CCND1 at transcription and translation levels. Overall, our findings identified hsa_circ_0032449 as an essential PP cell-fate specification regulator, indicating a promising potential in clinical applications and basic research.

LncRNA Malat1 regulates iPSC-derived β-cell differentiation by targeting the miR-15b-5p/Ihh axis

BACKGROUND

Differentiation of induced pluripotent stem cells (iPSCs)-derived β-like cells is a novel strategy for treatment of type 1 diabetes. Elucidation of the regulatory mechanisms of long noncoding RNAs (lncRNAs) in β-like cells derived from iPSCs is important for understanding the development of the pancreas and pancreatic β-cells and may improve the quality of β-like cells for stem cell therapy.

METHODS

β-like cells were derived from iPSCs in a three-step protocol. RNA sequencing and bioinformatics analysis were carried out to screen the differentially expressed lncRNAs and identify the putative target genes separately. LncRNA Malat1 was chosen for further research. Series of loss and gain of functions experiments were performed to study the biological function of LncRNA Malat1. Quantitative real-time PCR (qRT-PCR), Western blot (WB) analysis and immunofluorescence (IF) staining were carried out to separately detect the functions of pancreatic β-cells at the mRNA and protein levels. Cytoplasmic and nuclear RNA fractionation and fluorescence in situ hybridization (FISH) were used to determine the subcellar location of lncRNA Malat1 in β-like cells. Enzyme-linked immunosorbent assays (ELISAs) were performed to examine the differentiation and insulin secretion of β-like cells after stimulation with different glucose concentrations. Structural interactions between lncRNA Malat1 and miR-15b-5p and between miR-15b-5p/Ihh were detected by dual luciferase reporter assays (LRAs).

RESULTS

We found that the expression of lncRNA Malat1 declined during differentiation, and overexpression (OE) of lncRNA Malat1 notably impaired the differentiation and maturation of β-like cells derived from iPSCs in vitro and in vivo. Most importantly, lncRNA Malat1 could function as a competing endogenous RNA (ceRNA) of miR-15b-5p to regulate the expression of Ihh according to bioinformatics prediction, mechanistic analysis and downstream experiments.

CONCLUSION

This study established an unreported regulatory network of lncRNA Malat1 and the miR-15b-5p/Ihh axis during the differentiation of iPSCs into β-like cells. In addition to acting as an oncogene promoting tumorigenesis, lncRNA Malat1 may be an effective and novel target for treatment of diabetes in the future.

Ferroptosis: potential targets and emerging roles in pancreatic diseases

Ferroptosis is a newly discovered form of regulatory cell death characterized by excessive iron-dependent lipid peroxidation. In the past decade, significant breakthroughs have been made in comprehending the features and regulatory mechanisms of ferroptosis, and it has been confirmed that ferroptosis plays a pivotal role in the pathophysiological processes of various diseases, including tumors, inflammation, neurodegenerative diseases, and infectious diseases. The pancreas, which is the second largest digestive gland in the human body and has both endocrine and exocrine functions, is a vital organ for controlling digestion and metabolism. In recent years, numerous studies have confirmed that ferroptosis is closely related to pancreatic diseases, which is attributed to abnormal iron accumulation, as an essential biochemical feature of ferroptosis, is often present in the pathological processes of various pancreatic exocrine and endocrine diseases and the vulnerability of the pancreas to oxidative stress stimulation and damage. Therefore, comprehending the regulatory mechanism of ferroptosis in pancreatic diseases may provide valuable new insights into treatment strategies. In this review, we first summarize the hallmark features of ferroptosis and then analyze the exact mechanisms by which ferroptosis is precisely regulated at multiple levels and links, including iron metabolism, lipid metabolism, the GPX4-mediated ferroptosis defense system, the GPX4-independent ferroptosis defense system, and the regulation of autophagy on ferroptosis. Finally, we discuss the role of ferroptosis in the occurrence and development of pancreatic diseases and summarize the feasibility and limitations of ferroptosis as a therapeutic target for pancreatic diseases.

GABA treatment does not induce neogenesis of new endocrine cells from pancreatic ductal cells

Previous studies indicated that ductal cells can contribute to endocrine neogenesis in adult rodents after alpha cells convert into beta cells. This can occur through Pax4 mis-expression in alpha cells or through long-term administration of gamma-aminobutyric acid (GABA) to healthy mice. GABA has also been reported to increase the number of beta cells through direct effects on their proliferation, but only in specific genetic mouse backgrounds. To test whether GABA induces neogenesis of beta cells from ductal cells or affects pancreatic cell proliferation, we administered GABA or saline over 2 or 6 months to Sox9CreER;R26R^YFP mice in which 60-80% of large or small ducts were efficiently lineage labeled. We did not observe any increases in islet neogenesis from ductal cells between 1 and 2 months of age in saline treated mice, nor between 2 and 6 months of saline treatment, supporting previous studies indicating that adult ductal cells do not give rise to new endocrine cells during homeostasis. Unlike previous reports, we did not observe an increase in beta cell neogenesis after 2 or 6 months of GABA administration. Nor did we observe a significant increase in the pancreatic islet area, the number of insulin and glucagon double positive cells, or cell proliferation in the pancreas. This indicates that the effect of long term GABA administration on the pancreas is minimal or highly context dependent.

From diabetic hyperglycemia to cerebrovascular Damage: A narrative review

Diabetes mellitus is a globally significant disease that can lead to systemic complications, particularly vascular damage, including cardiovascular and cerebrovascular diseases of relevance. The physiological changes resulting from the imbalance in blood glucose levels play a crucial role in initiating vascular endothelial damage. Elevated glucose levels can also penetrate the central nervous system, triggering diabetic encephalopathy characterized by oxidative damage to brain components and activation of alternative and neurotoxic pathways. This brain damage increases the risk of ischemic stroke, a leading cause of mortality worldwide and a major cause of disability among surviving patients. The aim of this review is to highlight important pathways related to hyperglycemic damage that extend to the brain and result in vascular dysfunction, ultimately leading to the occurrence of a stroke. Understanding how diabetes mellitus contributes to the development of ischemic stroke and its impact on patient outcomes is crucial for implementing therapeutic strategies that reduce the incidence of diabetes mellitus and its complications, ultimately decreasing morbidity and mortality associated with the disease.

Hepatic insulin synthesis increases in rat models of diabetes mellitus type 1 and 2 differently

Insulin-positive (+) cells (IPCs), detected in multiple organs, are of great interest as a probable alternative to ameliorate pancreatic beta-cells dysfunction and insulin deficiency in diabetes. Liver is a potential source of IPCs due to it common embryological origin with pancreas. We previously demonstrated the presence of IPCs in the liver of healthy and diabetic rats, but detailed description and analysis of the factors, which potentially can induced ectopic hepatic expression of insulin in type 1 (T1D) and type 2 diabetes (T2D), were not performed. In present study we evaluate mass of hepatic IPCs in the rat models of T1D and T2D and discuss factors, which may stimulate it generation: glycaemia, organ injury, involving of hepatic stem/progenitor cell compartment, expression of transcription factors and inflammation. Quantity of IPCs in the liver was up by 1.7-fold in rats with T1D and 10-fold in T2D compared to non-diabetic (ND) rats. We concluded that ectopic hepatic expression of insulin gene is activated by combined action of a number of factors, with inflammation playing a decision role.

NEUROD2 function is dispensable for human pancreatic β cell specification

Introduction

The molecular programs regulating human pancreatic endocrine cell induction and fate allocation are not well deciphered. Here, we investigated the spatiotemporal expression pattern and the function of the neurogenic differentiation factor 2 (NEUROD2) during human endocrinogenesis.

Methods

Using Crispr-Cas9 gene editing, we generated a reporter knock-in transcription factor (TF) knock-out human inducible pluripotent stem cell (iPSC) line in which the open reading frame of both NEUROD2 alleles are replaced by a nuclear histone 2B-Venus reporter (NEUROD2nVenus/nVenus).

Results

We identified a transient expression of NEUROD2 mRNA and its nuclear Venus reporter activity at the stage of human endocrine progenitor formation in an iPSC differentiation model. This expression profile is similar to what was previously reported in mice, uncovering an evolutionarily conserved gene expression pattern of NEUROD2 during endocrinogenesis. In vitro differentiation of the generated homozygous NEUROD2nVenus/nVenus iPSC line towards human endocrine lineages uncovered no significant impact upon the loss of NEUROD2 on endocrine cell induction. Moreover, analysis of endocrine cell specification revealed no striking changes in the generation of insulin-producing b cells and glucagon-secreting a cells upon lack of NEUROD2.

Discussion

Overall, our results suggest that NEUROD2 is expendable for human b cell formation in vitro.

Targeting β Cells with Cathelicidin Nanomedicines Improves Insulin Function and Pancreas Regeneration in Type 1 Diabetic Rats

Type 1 diabetes (T1D) is an incurable condition with an increasing incidence worldwide, in which the hallmark is the autoimmune destruction of pancreatic insulin-producing β cells. Cathelicidin-based peptides have been shown to improve β cell function and neogenesis and may thus be relevant while developing T1D therapeutics. In this work, a cathelicidin-derived peptide, LLKKK18, was loaded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), surface-functionalized with exenatide toward a GLP-1 receptor, aiming the β cell-targeted delivery of the peptide. The NPs present a mean size of around 100 nm and showed long-term stability, narrow size distribution, and negative ζ-potential (-10 mV). The LLKKK18 association efficiency and loading were 62 and 2.9%, respectively, presenting slow and sustained in vitro release under simulated physiologic fluids. Glucose-stimulated insulin release in the INS-1E cell line was observed in the presence of the peptide. In addition, NPs showed a strong association with β cells from isolated rat islets. After administration to diabetic rats, NPs induced a significant reduction of the hyperglycemic state, an improvement in the pancreatic insulin content, and glucose tolerance. Also remarkable, a considerable increase in the β cell mass in the pancreas was observed. Overall, this novel and versatile nanomedicine showed glucoregulatory ability and can pave the way for the development of a new generation of therapeutic approaches for T1D treatment.

Reprogramming of pancreatic islet cells for regeneration and rejuvenation

The pancreatic β cell, which produces insulin, is a terminally differentiated cell type that divides rarely. Consequently, the regenerative ability of β cells is limited and irreversible diabetes occurs after severe loss of β-cell function. In view of such poor regenerative capacity, considerable research efforts have been made to promote the expansion of functional insulin-producing cells as a regenerative therapy for diabetes. Here, we discuss recent findings regarding the robust expansion of functional mature islet cells both in vivo and ex vivo through MYCL-mediated reprogramming. We also describe the potential prospects for the application of reprogramming technologies to regenerative therapy and rejuvenation of islet cells.

Transcriptional signature of islet neogenesis-associated protein peptide-treated rat pancreatic islets reveals induction of novel long non-coding RNAs

Background

Diabetes mellitus is characterized by chronic hyperglycemia with loss of β-cell function and mass. An attractive therapeutic approach to treat patients with diabetes in a non-invasive way is to harness the innate regenerative potential of the pancreas. The Islet Neogenesis-Associated Protein pentadecapeptide (INGAP-PP) has been shown to induce β-cell regeneration and improve their function in rodents. To investigate its possible mechanism of action, we report here the global transcriptional effects induced by the short-term INGAP-PP in vitro treatment of adult rat pancreatic islets.

Methods and findings

Rat pancreatic islets were cultured in vitro in the presence of INGAP-PP for 4 days, and RNA-seq was generated from triplicate treated and control islet samples. We performed a de novo rat gene annotation based on the alignment of RNA-seq reads. The list of INGAP-PP-regulated genes was integrated with epigenomic data. Using the new gene annotation generated in this work, we quantified RNA-seq data profiled in INS-1 cells treated with IL1β, IL1β+Calcipotriol (a vitamin D agonist) or vehicle, and single-cell RNA-seq data profiled in rat pancreatic islets. We found 1,669 differentially expressed genes by INGAP-PP treatment, including dozens of previously unannotated rat transcripts. Genes differentially expressed by the INGAP-PP treatment included a subset of upregulated transcripts that are associated with vitamin D receptor activation. Supported by epigenomic and single-cell RNA-seq data, we identified 9 previously unannotated long noncoding RNAs (lncRNAs) upregulated by INGAP-PP, some of which are also differentially regulated by IL1β and vitamin D in β-cells. These include Ri-lnc1, which is enriched in mature β-cells.

Conclusions

Our results reveal the transcriptional program that could explain the enhancement of INGAP-PP-mediated physiological effects on β-cell mass and function. We identified novel lncRNAs that are induced by INGAP-PP in rat islets, some of which are selectively expressed in pancreatic β-cells and downregulated by IL1β treatment of INS-1 cells. Our results suggest a relevant function for Ri-lnc1 in β-cells. These findings are expected to provide the basis for a deeper understanding of islet translational results from rodents to humans, with the ultimate goal of designing new therapies for people with diabetes.

BET inhibition rescues ciliogenesis and ameliorates pancreatitis-driven phenotypic changes in mice with Par3 loss

The apical-basal polarity of pancreatic acinar cells is essential for maintaining tissue architecture. However, the mechanisms by which polarity proteins regulate acinar pancreas tissue homeostasis are poorly understood. Here, we evaluate the role of Par3 in acinar pancreas injury and homeostasis. While Par3 loss in the mouse pancreas disrupts tight junctions, Par3 loss is dispensable for pancreatogenesis. However, with aging, Par3 loss results in low-grade inflammation, acinar degeneration, and pancreatic lipomatosis. Par3 loss also exacerbates pancreatitis-induced acinar cell loss, resulting in pronounced pancreatic lipomatosis and failure to regenerate. Moreover, Par3 loss in mice harboring mutant Kras causes extensive pancreatic intraepithelial neoplastic (PanIN) lesions and large pancreatic cysts. We also show that Par3 loss restricts injury-induced primary ciliogenesis. Significantly, targeting BET proteins enhances primary ciliogenesis during pancreatitis-induced injury and, in mice with Par3 loss, limits pancreatitis-induced acinar loss and facilitates acinar cell regeneration. Combined, this study demonstrates how Par3 restrains pancreatitis- and Kras-induced changes in the pancreas and identifies a potential role for BET inhibitors to attenuate pancreas injury and facilitate pancreas tissue regeneration.

Deciphering early human pancreas development at the single-cell level

Understanding pancreas development can provide clues for better treatments of pancreatic diseases. However, the molecular heterogeneity and developmental trajectory of the early human pancreas are poorly explored. Here, we performed large-scale single-cell RNA sequencing and single-cell assay for transposase accessible chromatin sequencing of human embryonic pancreas tissue obtained from first-trimester embryos. We unraveled the molecular heterogeneity, developmental trajectories and regulatory networks of the major cell types. The results reveal that dorsal pancreatic multipotent cells in humans exhibit different gene expression patterns than ventral multipotent cells. Pancreato-biliary progenitors that generate ventral multipotent cells in humans were identified. Notch and MAPK signals from mesenchymal cells regulate the differentiation of multipotent cells into trunk and duct cells. Notably, we identified endocrine progenitor subclusters with different differentiation potentials. Although the developmental trajectories are largely conserved between humans and mice, some distinct gene expression patterns have also been identified. Overall, we provide a comprehensive landscape of early human pancreas development to understand its lineage transitions and molecular complexity.

Evaluation of in vivo and ex vivo pre-treated bone marrow-derived mesenchymal stem cells with resveratrol in streptozotocin-induced type 1 diabetic rats

OBJECTIVES

To compare the therapeutic potential of rat bone marrow-derived mesenchymal stem cells (BM-MSCs) preconditioned ex-vivo with resveratrol (MCR) and BM-MSCs isolated from resveratrol-pre-treated rats (MTR) in type-1 diabetic rats.

METHODS

Type-1 diabetes was induced by a single streptozotocin injection (50 mg/kg; ip) in 24 rats. Following the confirmation of T1DM, diabetic rats were randomly divided into four groups: diabetic control (DC), diabetic rats treated with insulin subcutaneous (7.5 IU/kg/day), diabetic rats treated with MCR cells (3 × 106cells/rat, intravenous) and diabetic rats treated with MTR cells (3 × 106cells/rat, intravenous). Rats were sacrificed 4 weeks following cellular transplantation.

KEY FINDINGS

Untreated diabetic rats suffered from pancreatic cell damage, had high blood glucose levels, increased apoptotic, fibrosis, and oxidative stress markers and decreased survival and pancreatic regeneration parameters. Both MSCs preconditioned ex-vivo with RES and MSCs isolated from rats pre-treated with RES homed successfully in injured pancreas and showed therapeutic potential in the treatment of STZ-induced T1DM. MCR cells showed better efficiency than MTR cells.

CONCLUSIONS

The pre-conditioning of BM-MSCs with resveratrol may be a promising therapeutic possibility in T1DM. Resveratrol-preconditioned BM-MSCs encouraged effects almost comparable to that of exogenous insulin with the advantages of cured pancreas and restored islets not attained by insulin.

Pancreatic regenerative potential of manuka honey evidenced through pancreatic histology and levels of transcription factors in diabetic rat model

Background

Diabetes mellitus is a commonly occurring metabolic disorder accompanied by high morbidity and alarming mortality. Besides various available therapies, induction of pancreatic regeneration has emerged as a promising strategy for alleviating the damaging effect of diabetes. Honey, a potent antioxidative and anti-inflammatory agent, has been reported in the literature archive to exhibit favourable results in the regeneration process of several organ systems.

Design

The current research work was intended to explore the potential role of manuka honey in pancreatic regeneration in alloxan-induced diabetic rats by accessing the pancreatic histology and levels of relevant transcription factors, including MAFA, PDX-1, INS-1, INS-2, NEUROG3, NKX6-1, and NEUROD. An equal number of rats were allocated to all four experimental groups: normal, negative control, positive control, and treatment group. Diabetes was induced in all groups except normal through a single intraperitoneal dose of alloxan monohydrate. No subsequent treatment was given to the negative control group, while the positive control and treatment groups were supplemented with metformin (150 mg/kg/day) and manuka honey (3 g/kg/day), respectively.

Results

Statistical comparison of glucose and insulin levels, oxidative stress indicators, changes in the architecture of pancreatic islets, and expression levels of regeneration-associated transcription factors advocated the potential role of manuka honey in ameliorating the alloxan-induced hyperglycaemia, hyperinsulinemia, oxidative stress, and necrotic changes in islets along with significant upregulation of relevant transcription factors.

Conclusion

This suggests to us the auspicious role of antioxidants in honey in pancreatic regeneration and advocates the favourable role of manuka honey in combating diabetes mellitus.

Tff2 defines transit-amplifying pancreatic acinar progenitors that lack regenerative potential and are protective against Kras-driven carcinogenesis

While adult pancreatic stem cells are thought not to exist, it is now appreciated that the acinar compartment harbors progenitors, including tissue-repairing facultative progenitors (FPs). Here, we study a pancreatic acinar population marked by trefoil factor 2 (Tff2) expression. Long-term lineage tracing and single-cell RNA sequencing (scRNA-seq) analysis of Tff2-DTR-CreERT2-targeted cells defines a transit-amplifying progenitor (TAP) population that contributes to normal homeostasis. Following acute and chronic injury, Tff2+ cells, distinct from FPs, undergo depopulation but are eventually replenished. At baseline, oncogenic KrasG12D-targeted Tff2+ cells are resistant to PDAC initiation. However, KrasG12D activation in Tff2+ cells leads to survival and clonal expansion following pancreatitis and a cancer stem/progenitor cell-like state. Selective ablation of Tff2+ cells prior to KrasG12D activation in Mist1+ acinar or Dclk1+ FP cells results in enhanced tumorigenesis, which can be partially rescued by adenoviral Tff2 treatment. Together, Tff2 defines a pancreatic TAP population that protects against Kras-driven carcinogenesis.

Protective potential of fish oil supplementation against insulin resistance and pancreatic islet damage in STZ-induced Wistar rats

Background

Fish oil, which is regarded as the primary source of omega-3 fatty acids, has been long studied for its potential as an antidiabetic therapy. However, its protective ability against insulin resistance and pancreatic islet alteration remains unclear and controversial.

Aim

To investigate the beneficial effects of fish oil consumption on the progression of insulin resistance and pancreatic islet dysfunction in a rat model of diabetes.

Methods

Diabetic rats model (n = 30) were divided into five groups and received; 1) NS injection + NS oral (normal control); 2) NS injection + 3 g/kg fish oil (fish oil control); 3) streptozotocin (STZ) injection + NS oral [diabetes control (DC)]; 4) STZ injection + 1 g/kg fish oil (DFO1); and 5) STZ injection + 3 g/kg fish oil (DFO3). Fasting blood insulin was analyzed by commercial rat insulin enzyme-linked immunosorbent assay; meanwhile, the determination of insulin sensitivity was calculated by homeostatic model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of beta-cell function. A histological study was conducted on pancreas tissue using H and E staining.

Results

Fish oil supplementation reduced hyperglycemia and ameliorated HOMA-IR in STZ-induced animal models indicating that fish oil supplementation improved insulin sensitivity. Furthermore, animals treated with fish oil at a dose of 3 g/kg (DFO3) showed an enhancement in pancreatic islets, which was displayed by less abnormal structures than DC animals. This could imply that the administration of fish oil, especially rich in bioactive omega-3 fatty acids effectively inhibits insulin resistance and restore islet of Langerhans alteration in rats injected with STZ.

Conclusion

Thus, the current study suggested that fish oil supplementation could support the treatment of diabetes but should not be considered as an alternative therapy.

Pancreatic Stellate Cells and the Targeted Therapeutic Strategies in Chronic Pancreatitis

Chronic pancreatitis (CP) is a disease characterized by inflammatory recurrence that accompanies the development of pancreatic fibrosis. As the mystery of CP pathogenesis is gradually revealed, accumulating evidence suggests that the activation of pancreatic stellate cells (PSCs) and the appearance of a myofibroblast-like phenotype are the key gatekeepers in the development of CP. Targeting PSCs to prevent their activation and conversion to a myofibroblast-like phenotype, as well as increasing antioxidant capacity to counteract ongoing oxidative stress, are effective strategies for preventing or treating CP. Therefore, we reviewed the crosstalk between CP and pancreatic fibrosis, summarized the activation mechanisms of PSCs, and investigated potential CP therapeutic strategies targeting PSCs, including, but not limited to, anti-fibrosis therapy, antioxidant therapy, and gene therapy. Meanwhile, the above therapeutic strategies are selected in order to update the available phytopharmaceuticals as novel complementary or alternative approaches for the prevention and treatment of CP to clarify their potential mechanisms of action and their relevant molecular targets, aiming to provide the most comprehensive therapeutic treatment direction for CP and to bring new hope to CP patients.

scKINETICS: inference of regulatory velocity with single-cell transcriptomics data

MOTIVATION

Transcriptional dynamics are governed by the action of regulatory proteins and are fundamental to systems ranging from normal development to disease. RNA velocity methods for tracking phenotypic dynamics ignore information on the regulatory drivers of gene expression variability through time.

RESULTS

We introduce scKINETICS (Key regulatory Interaction NETwork for Inferring Cell Speed), a dynamical model of gene expression change which is fit with the simultaneous learning of per-cell transcriptional velocities and a governing gene regulatory network. Fitting is accomplished through an expectation-maximization approach designed to learn the impact of each regulator on its target genes, leveraging biologically motivated priors from epigenetic data, gene-gene coexpression, and constraints on cells' future states imposed by the phenotypic manifold. Applying this approach to an acute pancreatitis dataset recapitulates a well-studied axis of acinar-to-ductal transdifferentiation whilst proposing novel regulators of this process, including factors with previously appreciated roles in driving pancreatic tumorigenesis. In benchmarking experiments, we show that scKINETICS successfully extends and improves existing velocity approaches to generate interpretable, mechanistic models of gene regulatory dynamics.

AVAILABILITY AND IMPLEMENTATION

All python code and an accompanying Jupyter notebook with demonstrations are available at http://github.com/dpeerlab/scKINETICS.

Serum Metabolite Biomarkers for Pancreatic Tumors: Neuroendocrine and Pancreatic Ductal Adenocarcinomas-A Preliminary Study

BACKGROUND

Pancreatic cancer is the most common pancreatic solid malignancy with an aggressive clinical course and low survival rate. There are a limited number of reliable prognostic biomarkers and a need to understand the pathogenesis of pancreatic tumors; neuroendocrine (PNET) and pancreatic ductal adenocarcinomas (PDAC) encouraged us to analyze the serum metabolome of pancreatic tumors and disturbances in the metabolism of PDAC and PNET.

METHODS

Using the AbsoluteIDQ^® p180 kit (Biocrates Life Sciences AG, Innsbruck, Austria) with liquid chromatography-mass spectrometry (LC-MS), we identified changes in metabolite profiles and disrupted metabolic pathways serum of NET and PDAC patients.

RESULTS

The concentration of six metabolites showed statistically significant differences between the control group and PDAC patients (p.adj < 0.05). Glutamine (Gln), acetylcarnitine (C2), and citrulline (Cit) presented a lower concentration in the serum of PDAC patients, while phosphatidylcholine aa C32:0 (PC aa C32:0), sphingomyelin C26:1 (SM C26:1), and glutamic acid (Glu) achieved higher concentrations compared to serum samples from healthy individuals. Five of the tested metabolites: C2 (FC = 8.67), and serotonin (FC = 2.68) reached higher concentration values in the PNET serum samples compared to PDAC, while phosphatidylcholine aa C34:1 (PC aa C34:1) (FC = -1.46 (0.68)) had a higher concentration in the PDAC samples. The area under the curves (AUC) of the receiver operating characteristic (ROC) curves presented diagnostic power to discriminate pancreatic tumor patients, which were highest for acylcarnitines: C2 with AUC = 0.93, serotonin with AUC = 0.85, and PC aa C34:1 with AUC = 0.86.

CONCLUSIONS

The observations presented provide better insight into the metabolism of pancreatic tumors, and improve the diagnosis and classification of tumors. Serum-circulating metabolites can be easily monitored without invasive procedures and show the present clinical patients' condition, helping with pharmacological treatment or dietary strategies.

Membrane protease prostasin promotes insulin secretion by regulating the epidermal growth factor receptor pathway

Prostasin (PRSS8) is a serine protease that metabolizes and moderates the effect of specific substrates. Epidermal growth factor receptor (EGFR), which modulates insulin secretion and pancreatic β-cell proliferation, is regulated via proteolytic shedding by PRSS8. We first detected PRSS8 expression in β-cells of pancreatic islets of mice. To better understand the molecular processes involved in PRSS8-associated insulin secretion, pancreatic β-cell-specific PRSS8 knockout (βKO) and PRSS8-overexpressing (βTG) male mice were generated. We found that glucose intolerance and reduction in glucose-stimulated insulin secretion developed in βKO mice compared with the control subjects. A higher response to glucose was noted in islets retrieved from βTG mice. Erlotinib, a specific blocker of EGFR, blocks EGF- and glucose-stimulated secretion of insulin among MIN6 cells, and glucose improves EGF release from β-cells. After silencing PRSS8 in MIN6 cells, glucose-stimulated insulin secretion decreased, and EGFR signaling was impaired. Conversely, overexpression of PRSS8 in MIN6 cells induced higher concentrations of both basal and glucose-stimulated insulin secretion and increased phospho-EGFR concentrations. Furthermore, short-term exposure to glucose improved the concentration of endogenous PRSS8 in MIN6 cells through inhibition of intracellular degradation. These findings suggest that PRSS8 is involved in glucose-dependent physiological regulation of insulin secretion via the EGF-EGFR signaling pathway in pancreatic β-cells.

Effects of a Ganoderma lucidum Proteoglycan on Type 2 Diabetic Rats and the Recovery of Rat Pancreatic Islets

Type 2 diabetes (T2D) results from both insulin resistance and pancreatic β-cell dysfunction. A natural proteoglycan extracted from Ganoderma lucidum, namely, FYGL, has been demonstrated to be capable of ameliorating insulin resistance in previous work. In this work, a T2D rat model induced by streptozocin (STZ) and a high-fat diet was used to investigate the effects of FYGL on pancreatic functions, and the transcriptomics of the rat pancreas was used to investigate the biological processes (BP) and signal pathways influenced by FYGL on the gene basis. Furthermore, the results of transcriptomics were verified both by histopathological analyses and protein expression. The studies showed that FYGL positively regulated T2D-related BP and signaling pathways and recovered the pancreatic function, therefore ameliorating hyperglycemia and hyperlipidemia in vivo. Importantly, the recovery of the pancreatic function suggested a crucial strategy to radically treat T2D.

Cancer Stem Cells are Actually Stem Cells with Disordered Differentiation: the Monophyletic Origin of Cancer

Cancer stem cells (CSCs) play an important role in cancer development. Based on advancements in CSC research, we propose a monophyletic model of cancer. This model is based on the idea that CSCs are stem cells with disordered differentiation whose original purpose was to repair damaged tissues. Inflammatory responses and damage repair signals are crucial for the creation and maintenance of CSCs. Normal quiescent stem cells are activated by environmental stimulation, such as an inflammatory response, and undergo cell division and differentiation. In the initial stage of cancer development, stem cell differentiation leads to heteromorphism due to the accumulation of gene mutations, resulting in the development of metaplasia or precancerosis. In the second stage, accumulated mutations induce poor differentiation and lead to cancer development. The monophyletic model illustrates the evolution, biological behavior, and hallmarks of CSCs, proposes a concise understanding of the origin of cancer, and may encourage a novel therapeutic approach.

Stomach-derived human insulin-secreting organoids restore glucose homeostasis

Gut stem cells are accessible by biopsy and propagate robustly in culture, offering an invaluable resource for autologous cell therapies. Insulin-producing cells can be induced in mouse gut, but it has not been possible to generate abundant and durable insulin-secreting cells from human gut tissues to evaluate their potential as a cell therapy for diabetes. Here we describe a protocol to differentiate cultured human gastric stem cells into pancreatic islet-like organoids containing gastric insulin-secreting (GINS) cells that resemble β-cells in molecular hallmarks and function. Sequential activation of the inducing factors NGN3 and PDX1-MAFA led human gastric stem cells onto a distinctive differentiation path, including a SOX4High endocrine and GalaninHigh GINS precursor, before adopting β-cell identity, at efficiencies close to 70%. GINS organoids acquired glucose-stimulated insulin secretion in 10 days and restored glucose homeostasis for over 100 days in diabetic mice after transplantation, providing proof of concept for a promising approach to treat diabetes.

Role of Cell-Based Therapies in T2D

Type 2 diabetes mellitus (T2D) has become a global epidemic affecting the health of millions of people. T2D is a complex and multifactorial metabolic disease, largely characterized by a combination of impaired insulin secretion from β cells residing within the islets of the pancreas and peripheral insulin resistance. In this article, we discuss the current state and risk factors for T2D, conventional treatment options, and upcoming strategies, including progress in the areas of allogeneic and xenogeneic islet transplantation, with a major focus on stem cell-derived β cells and associated technologies.

Mitochondrial complex III deficiency drives c-MYC overexpression and illicit cell cycle entry leading to senescence and segmental progeria

Accumulating evidence suggests mitochondria as key modulators of normal and premature aging, yet whether primary oxidative phosphorylation (OXPHOS) deficiency can cause progeroid disease remains unclear. Here, we show that mice with severe isolated respiratory complex III (CIII) deficiency display nuclear DNA damage, cell cycle arrest, aberrant mitoses, and cellular senescence in the affected organs such as liver and kidney, and a systemic phenotype resembling juvenile-onset progeroid syndromes. Mechanistically, CIII deficiency triggers presymptomatic cancer-like c-MYC upregulation followed by excessive anabolic metabolism and illicit cell proliferation against lack of energy and biosynthetic precursors. Transgenic alternative oxidase dampens mitochondrial integrated stress response and the c-MYC induction, suppresses the illicit proliferation, and prevents juvenile lethality despite that canonical OXPHOS-linked functions remain uncorrected. Inhibition of c-MYC with the dominant-negative Omomyc protein relieves the DNA damage in CIII-deficient hepatocytes in vivo. Our results connect primary OXPHOS deficiency to genomic instability and progeroid pathogenesis and suggest that targeting c-MYC and aberrant cell proliferation may be therapeutic in mitochondrial diseases.

Role of selenium in type 2 diabetes, insulin resistance and insulin secretion

Selenium is a trace mineral essential for life that acts physiologically through selenoproteins. Among other actions, the endogenous antioxidant selenoprotein glutathione peroxidase and the selenium transporter in blood, selenoprotein P, seem to play an important role in type 2 diabetes mellitus and insulin resistance by weakening the insulin signaling cascade through different mechanisms. Recent findings also suggest that selenoproteins also affect insulin biosynthesis and insulin secretion. This review discussed the role of selenium in type 2 diabetes and the complex interplay between selenoproteins and insulin pathways.

Die Bauchspeicheldrüse – der Blick fürs Ganze

Eine Pathologie der Bauchspeicheldrüse ist vielfach Wegbereiter für weitere Pathologien desselben Organs. Grund dafür ist die enge Verknüpfung der endokrinen und exokrinen Anteile sowie die vergleichbaren Pathogenese-Faktoren der unterschiedlichen Erkrankungen. Phytotherapeutika und Komplexhomöopathika sind aufgrund ihrer Multi-Target-Wirkungen und der großen therapeutischen Breite ideale Mittel, um bei Diabetes, Exokriner Pankreas-Insuffizienz und chronischer Pankreatitis helfend einzugreifen.

Changes in Pancreatic Senescence Mediate Pancreatic Diseases

In recent years, there has been a significant increase in age-related diseases due to the improvement in life expectancy worldwide. The pancreas undergoes various morphological and pathological changes with aging, such as pancreatic atrophy, fatty degeneration, fibrosis, inflammatory cell infiltration, and exocrine pancreatic metaplasia. Meanwhile, these may predispose the individuals to aging-related diseases, such as diabetes, dyspepsia, pancreatic ductal adenocarcinoma, and pancreatitis, as the endocrine and exocrine functions of the pancreas are significantly affected by aging. Pancreatic senescence is associated with various underlying factors including genetic damage, DNA methylation, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and inflammation. This paper reviews the alternations of morphologies and functions in the aging pancreas, especially β-cells, closely related to insulin secretion. Finally, we summarize the mechanisms of pancreatic senescence to provide potential targets for treating pancreatic aging-related diseases.

Fufang-zhenzhu-tiaozhi formula protects islet against injury and promotes β cell regeneration in diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang-zhenzhu-tiaozhi formula (FTZ) is a patented preparation of traditional Chinese medicine that has been used to treat hyperglycemia and hyperlipidemia in the clinic for almost 10 years. Our previous study had demonstrated that FTZ can protect islet β cell injury in vitro. However, the efficacy of FTZ on β cell regeneration in vivo and the involved anti-diabetic mechanism remains unknown.

AIM OF THE STUDY

We aim to investigate the effects of FTZ as a good remedy for islet protection and β cell regeneration, and to reveal the underlying mechanism.

MATERIALS AND METHODS

C57BL/6 mice were fed with high-fat diet for 3 weeks and then intraperitoneally injected with streptozotocin (90 mg/kg/d × 1 d) to establish type 2 diabetes (T2D) models. Mice in each group were divided into three batches that sacrificed after 3, 7 and 28 days of FTZ administration. Body weight, blood glucose, and oral glucose tolerance test were measured at indicated time points. Fasting insulin was determined by enzyme-linked immunosorbent assay (ELISA) kit. Neonatal β cell was assessed by insulin & PCNA double immunofluorescence staining, and the underlying mechanisms related to β cell regeneration were further performed by hematoxylin-eosin staining, insulin & glucagon double immunofluorescence staining and Western blot.

RESULTS

FTZ and metformin can significantly help with the symptoms of DM, such as alleviating weight loss, reducing blood glucose, improving the level of insulin in vivo, and relieving insulin resistance, suggesting FTZ and metformin treatment maintained the normal morphological function of islet. Notably, β cell regeneration, which is indicated by insulin and PCNA double-positive cells, was promoted by FTZ, whereas few neonatal β cells were observed in metformin group. Hematoxylin-eosin staining, and its quantification results showed that FTZ effectively prevented the invasion of inflammatory cells into the islets in diabetic mice. Most β cells in the islets of diabetic model mice were devoid, and the islets were almost all α cells, while the diabetic mice administered FTZ could still maintain about half of the β cells in the islet. Furthermore, FTZ upregulated the expression of critical transcription factors during β cell development and maturation (such as PDX-1, MAFA and NGN3) in diabetic mice.

CONCLUSIONS

FTZ can alleviate diabetes symptoms and promote β cell regeneration in diabetic mice. Moreover, FTZ promotes β cell regeneration by preserving islet (resisting inflammatory cells invading islets), maintaining the number of β cells in islets, and increasing the expression of PDX-1, MAFA and NGN3.

Risk Factors Associated with Acute Pancreatitis after Percutaneous Biliary Intervention: We Do Not Know Nearly Enough

Percutaneous transhepatic cholangiodrainage (PTCD) and percutaneous transhepatic biliary stenting (PTBS) may be used as a palliative treatment for inoperable patients with malignant biliary obstruction (MBO) to improve the prognosis and their quality of life. However, acute pancreatitis is a common and severe complication that cannot be ignored after PTCD and PTBS in patients with MBO. A few cases may develop severe pancreatitis with a higher mortality rate. In this study, we summarize the known risk factors for acute pancreatitis after percutaneous biliary interventional procedures and investigate possible risk factors to reduce its occurrence by early identifying high-risk patients and taking appropriate measures.

Use of a dual genetic system to decipher exocrine cell fate conversions in the adult pancreas

Unraveling cell fate plasticity during tissue homeostasis and repair can reveal actionable insights for stem cell biology and regenerative medicine. In the pancreas, it remains controversial whether lineage transdifferentiation among the exocrine cells occur under pathophysiological conditions. Here, to address this question, we used a dual recombinase-mediated genetic system that enables simultaneous tracing of pancreatic acinar and ductal cells using two distinct genetic reporters, avoiding the "ectopic" labeling by Cre-loxP recombination system. We found that acinar-to-ductal transdifferentiation occurs after pancreatic duct ligation or during caerulein-induced pancreatitis, but not during homeostasis or after partial pancreatectomy. On the other hand, pancreatic ductal cells contribute to new acinar cells after significant acinar cell loss. By genetic tracing of cell proliferation, we also quantify the cell proliferation dynamics and deduce the turnover rate of pancreatic exocrine lineages during homeostasis. Together, these results suggest that the lineage transdifferentiation happens between acinar cells and ductal cells in the pancreatic exocrine glands under specific conditions.

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.