Pancreatic stellate cells: Key players in pancreatic health and diseases (Review).

As a pluripotent cell, activated pancreatic stellate cells (PSCs) can differentiate into various pancreatic parenchymal cells and participate in the secretion of extracellular matrix and the repair of pancreatic damage. Additionally, PSCs characteristics allow them to contribute to pancreatic inflammation and carcinogenesis. Moreover, a detailed study of the pathogenesis of activated PSCs in pancreatic disease can offer promise for the development of innovative therapeutic strategies and improved patient prognoses. Therefore, the present study review aimed to examine the involvement of activated PSCs in pancreatic diseases and elucidate the underlying mechanisms to provide a viable therapeutic strategy for the management of pancreas­related diseases.

COMP promotes pancreatic fibrosis by activating pancreatic stellate cells through CD36-ERK/AKT signaling pathways.

BACKGROUND: Pancreatic fibrosis is one of the most important pathological features of chronic pancreatitis (CP) and pancreatic stellate cells (PSCs) are the key cells of fibrosis. As an extracellular matrix (ECM) glycoprotein, cartilage oligomeric matrix protein (COMP) is critical for collagen assembly and ECM stability and recent studies showed that COMP exert promoting fibrosis effect in the skin, lungs and liver. However, the role of COMP in activation of PSCs and pancreatic fibrosis remain unclear. We aimed to investigate the role and specific mechanisms of COMP in regulating the profibrotic phenotype of PSCs and pancreatic fibrosis. METHODS: ELISA method was used to determine serum COMP in patients with CP. Mice model of CP was established by repeated intraperitoneal injection of cerulein and pancreatic fibrosis was evaluated by Hematoxylin-Eosin staining (H&E) and Sirius red staining. Immunohistochemical staining was used to detect the expression changes of COMP and fibrosis marker such as α-SMA and Fibronectin in pancreatic tissue of mice. Cell Counting Kit-8, Wound Healing and Transwell assessed the proliferation and migration of human pancreatic stellate cells (HPSCs). Western blotting, qRT-PCR and immunofluorescence staining were performed to detect the expression of fibrosis marker, AKT and MAPK family proteins in HPSCs. RNA-seq omics analysis as well as small interfering RNA of COMP, recombinant human COMP (rCOMP), MEK inhibitors and PI3K inhibitors were used to study the effect and mechanism of COMP on activation of HPSCs. RESULTS: ELISA showed that the expression of COMP significantly increased in the serum of CP patients. H&E and Sirius red staining analysis showed that there was a large amount of collagen deposition in the mice in the CP model group and high expression of COMP, α-SMA, Fibronectin and Vimentin were observed in fibrotic tissues. TGF-ß1 stimulates the activation of HPSCs and increases the expression of COMP. Knockdown of COMP inhibited proliferation and migration of HPSCs. Further, RNA-seq omics analysis and validation experiments in vitro showed that rCOMP could significantly promote the proliferation and activation of HPSCs, which may be due to promoting the phosphorylation of ERK and AKT through membrane protein receptor CD36. rCOMP simultaneously increased the expression of α-SMA, Fibronectin and Collagen I in HPSCs. CONCLUSION: In conclusion, this study showed that COMP was up-regulated in CP fibrotic tissues and COMP induced the activation, proliferation and migration of PSCs through the CD36-ERK/AKT signaling pathway. COMP may be a potential therapeutic candidate for the treatment of CP. Interfering with the expression of COMP or the communication between COMP and CD36 on PSCs may be the next direction for therapeutic research.

Reactive Oxygen Species-Responsive Nanoparticles Toward Extracellular Matrix Normalization for Pancreatic Fibrosis Regression.

Pancreatic fibrosis (PF) is primarily characterized by aberrant production and degradation modes of extracellular matrix (ECM) components, resulting from the activation of pancreatic stellate cells (PSCs) and the pathological cross-linking of ECM mediated by lysyl oxidase (LOX) family members. The excessively deposited ECM increases matrix stiffness, and the over-accumulated reactive oxygen species (ROS) induces oxidative stress, which further stimulates the continuous activation of PSCs and advancing PF; challenging the strategy toward normalizing ECM homeostasis for the regression of PF. Herein, ROS-responsive and Vitamin A (VA) decorated micelles (named LR-SSVA) to reverse the imbalanced ECM homeostasis for ameliorating PF are designed and synthesized. Specifically, LR-SSVA selectively targets PSCs via VA, thereby effectively delivering siLOXL1 and resveratrol (RES) into the pancreas. The ROS-responsive released RES inhibits the overproduction of ECM by eliminating ROS and inactivating PSCs, meanwhile, the decreased expression of LOXL1 ameliorates the cross-linked collagen for easier degradation by collagenase which jointly normalizes ECM homeostasis and alleviates PF. This research shows that LR-SSVA is a safe and efficient ROS-response and PSC-targeted drug-delivery system for ECM normalization, which will propose an innovative and ideal platform for the reversal of PF.

Important roles of Hif1a in maternal or adult BPA exposure induced pancreatic injuries.

Bisphenol A (BPA) is a monomer to produce polycarbonate plastics and can be released into the environment through human activities, leading to its accumulation in animals, plants and humans through direct contact or environmental exposure. Epidemiological studies have reported that BPA exposure is associated with metabolic disorders. The pancreas is an important endocrine organ and plays an important role in metabolic disorders. To explore the possible long-term effects of BPA exposure on neonatal health, bioinformatic methods were used to identify differentially expressed genes (DEGs) by comparing the neonatal pancreas after maternal exposure to BPA with the adult pancreas after direct exposure to BPA. Two datasets about BPA exposure and pancreatic abnormality, GSE82175 and GSE126297 in Gene Expression Omnibus (GEO) at the National Center for Biotechnology Information (NCBI) were collected. Control (or BPA-exposed) offspring (maternal exposure) and Control (or BPA-exposed) adults (direct exposure) were defined as Control (or BPA) groups. The results showed that BPA disturbed the normal function of the pancreas in both offspring and adults, with offspring showing higher susceptibility to BPA than adults. Seventeen insulin secretion-related DEGs (Stxbp5l, Fam3d, Mia3, Igf1, Hif1a, Aqp1, Kif5b, Tiam1, Map4k4, Cyp51, Pde1c, Rab3c, Arntl, Clock, Edn3, Kcnb1, and Krt20) in the BPA group were identified, and 15 regulator DEGs (Zfp830, 4931431B13Rik, Egr1, Ddit4l, Cep55, G530011O06Rik, Hspa1b, Hspa1a, Cox6a2, Ibtk, Banf1, Slc35b2, Golt1b, Lrp8, and Pttg1) with opposite expression trends and a regulator gene Cerkl with the similar expression trend in the Control and BPA groups were identified. Hif1α might be an important molecular target for pancreatic cancer caused by BPA exposure, and pregnancy is a critical window of susceptibility to BPA exposure.

Acinar cells and the development of pancreatic fibrosis.

Pancreatic fibrosis is caused by excessive deposition of extracellular matrixes of collagen and fibronectin in the pancreatic tissue as a result of repeated injury often seen in patients with chronic pancreatic diseases. The most common causative conditions include inborn errors of metabolism, chemical toxicity and autoimmune disorders. Its pathophysiology is highly complex, including acinar cell injury, acinar stress response, duct dysfunction, pancreatic stellate cell activation, and persistent inflammatory response. However, the specific mechanism remains to be fully clarified. Although the current therapeutic strategies targeting pancreatic stellate cells show good efficacy in cell culture and animal models, they are not satisfactory in the clinic. Without effective intervention, pancreatic fibrosis can promote the transformation from pancreatitis to pancreatic cancer, one of the most lethal malignancies. In the normal pancreas, the acinar component accounts for 82% of the exocrine tissue. Abnormal acinar cells may activate pancreatic stellate cells directly as cellular source of fibrosis or indirectly via releasing various substances and initiate pancreatic fibrosis. A comprehensive understanding of the role of acinar cells in pancreatic fibrosis is critical for designing effective intervention strategies. In this review, we focus on the role of and mechanisms underlying pancreatic acinar injury in pancreatic fibrosis and their potential clinical significance.

Ascorbic acid reduces insulin resistance and pancreatic steatosis by regulating adipocyte hypertrophy in obese ovariectomized mice.

Ascorbic acid has been suggested to regulate obesity in obese male rodents. Moreover, increased adipocyte size has been associated with metabolic disease. Thus, we investigated the effects of ascorbic acid on adipocyte hypertrophy and insulin resistance in high-fat diet (HFD)-induced obese ovariectomized (OVX) C57BL/6J mice, an animal model of obese postmenopausal women. Administration of ascorbic acid (5% w/w in diet for 18 weeks) reduced the size of visceral adipocytes without changes in body weight and adipose tissue mass in HFD-fed obese OVX mice compared with obese OVX mice that did not receive ascorbic acid. Ascorbic acid inhibited adipose tissue inflammation, as shown by the decreased number of crown-like structures and CD68-positive macrophages in visceral adipose tissues. Ascorbic acid-treated mice exhibited improved hyperglycemia, hyperinsulinemia, and glucose and insulin tolerance compared with nontreated obese mice. Pancreatic islet size and insulin-positive ß-cell area in ascorbic acid-treated obese OVX mice decreased to the levels observed in low-fat diet-fed lean mice. Ascorbic acid also suppressed pancreatic triglyceride accumulation in obese mice. These results suggest that ascorbic acid may reduce insulin resistance and pancreatic steatosis partly by suppressing visceral adipocyte hypertrophy and adipose tissue inflammation in obese OVX mice.

Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases: Workshop Proceedings.

The Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases workshop was a 1.5-day scientific conference at the National Institutes of Health (Bethesda, MD) that engaged clinical and basic science investigators interested in diseases of the pancreas. This report provides a summary of the proceedings from the workshop. The goals of the workshop were to forge connections and identify gaps in knowledge that could guide future research directions. Presentations were segregated into six major theme areas, including 1) pancreas anatomy and physiology, 2) diabetes in the setting of exocrine disease, 3) metabolic influences on the exocrine pancreas, 4) genetic drivers of pancreatic diseases, 5) tools for integrated pancreatic analysis, and 6) implications of exocrine-endocrine cross talk. For each theme, multiple presentations were followed by panel discussions on specific topics relevant to each area of research; these are summarized here. Significantly, the discussions resulted in the identification of research gaps and opportunities for the field to address. In general, it was concluded that as a pancreas research community, we must more thoughtfully integrate our current knowledge of normal physiology as well as the disease mechanisms that underlie endocrine and exocrine disorders so that there is a better understanding of the interplay between these compartments.

PTRH2 is Necessary for Purkinje Cell Differentiation and Survival and its Loss Recapitulates Progressive Cerebellar Atrophy and Ataxia Seen in IMNEPD Patients.

Hom ozygous variants in the peptidyl-tRNA hydrolase 2 gene (PTRH2) cause infantile-onset multisystem neurologic, endocrine, and pancreatic disease. The objective is to delineate the mechanisms underlying the core cerebellar phenotype in this disease. For this, we generated constitutive (Ptrh2LoxPxhCMVCre, Ptrh2-/- mice) and Purkinje cell (PC) specific (Ptrh2LoxPxPcp2Cre, Ptrh2ΔPCmice) Ptrh2 mutant mouse models and investigated the effect of the loss of Ptrh2 on cerebellar development. We show that Ptrh2-/- knockout mice had severe postnatal runting and lethality by postnatal day 14. Ptrh2ΔPC PC specific knockout mice survived until adult age; however, they showed progressive cerebellar atrophy and functional cerebellar deficits with abnormal gait and ataxia. PCs of Ptrh2ΔPC mice had reduced cell size and density, stunted dendrites, and lower levels of ribosomal protein S6, a readout of the mammalian target of rapamycin pathway. By adulthood, there was a marked loss of PCs. Thus, we identify a cell autonomous requirement for PTRH2 in PC maturation and survival. Loss of PTRH2 in PCs leads to downregulation of the mTOR pathway and PC atrophy. This suggests a molecular mechanism underlying the ataxia and cerebellar atrophy seen in patients with PTRH2 mutations leading to infantile-onset multisystem neurologic, endocrine, and pancreatic disease.

Pancreatic fat infiltration, ß-cell function and insulin resistance: A study of the young patients with obesity.

OBJECTIVE: This study aimed to investigate the relationship between pancreatic fat infiltration (PFI) and glucose metabolism disorder, ß-cell function and insulin resistance in patients with obesity. METHODS: Pancreatic fat fraction (PFF) was quantified by MRI IDEAL-IQ technique. PFF greater than 6.2 % was defined as PFI, and 34 obese patients were divided into PFI and non-PFI groups. The 5-point plasma glucose and insulin values during oral glucose tolerance test (OGTT) were recorded. OGTT-derived indices of insulin resistance and ß-cell function were calculated. RESULTS: Glucose values levels at 0-120 min during OGTT were significantly higher and ß-cell function variables were lower in PFI group than non-PFI group. While indices of insulin resistance were not significantly different between two groups. Correlation analysis showed that PFF was positively correlated with glucose levels at 0, 30 and 60 min, negatively correlated with ß-cell function variables and not significantly correlated with indices of insulin resistance. However, these associations of PFF with ß-cell function and glucose levels were only present in type 2 diabetes mellitus (T2DM) group but not in non-T2DM group. CONCLUSION: There is an association between PFI and impaired ß-cell function, and increased pancreatic fat may be a potential risk factor for the development of T2DM.

Innate Lymphoid Cells: Emerging Players in Pancreatic Disease.

Common pancreatic diseases have caused significant economic and social burdens worldwide. The interstitial microenvironment is involved in and plays a crucial part in the occurrence and progression of pancreatic diseases. Innate lymphoid cells (ILCs), an innate population of immune cells which have only gradually entered our visual field in the last 10 years, play an important role in maintaining tissue homeostasis, regulating metabolism, and participating in regeneration and repair. Recent evidence indicates that ILCs in the pancreas, as well as in other tissues, are also key players in pancreatic disease and health. Herein, we examined the possible functions of different ILC subsets in common pancreatic diseases, including diabetes mellitus, pancreatitis and pancreatic cancer, and discussed the potential practical implications of the relevant findings for future further treatment of these pancreatic diseases.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography.

INTRODUCTION: There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS. METHODS: Patients with and without PS were evaluated prospectively. RESULTS: Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria. DISCUSSION/CONCLUSION: PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

Ferulic acid promotes muscle glucose uptake and modulate dysregulated redox balance and metabolic pathways in ferric-induced pancreatic oxidative injury.

The antidiabetic properties of ferulic acid and its protective role against Fe2+ -induced oxidative pancreatic injury were investigated in this study using in vitro and ex vivo models. Induction of oxidative injury in the pancreas was achieved by incubating normal pancreatic tissue with 0.1 mM FeSO4 and treated by co-incubating with different concentrations of ferulic acid for 30 min at 37°C. Ferulic acid inhibited the activities of α-glucosidase, α-amylase, and pancreatic lipase significantly (p < .05) and promoted glucose uptake in isolated rat psoas muscles. Induction of oxidative pancreatic injury caused significant (p < .05) depletion of glutathione (GSH) level, superoxide dismutase (SOD), and catalase activities, as well as elevation of malondialdehyde (MDA) and nitric oxide (NO) levels, acetylcholinesterase and chymotrypsin activities. Treatment of tissues with ferulic acid significantly (p < .05) reversed these levels and activities. LC-MS analysis of the extracted metabolites revealed 25% depletion of the normal metabolites with concomitant generation of m-Chlorohippuric acid, triglyceride, fructose 1,6-bisphosphate, and ganglioside GM1 in oxidative-injured pancreatic tissues. Treatment with ferulic acid restored uridine diphosphate glucuronic acid and adenosine tetraphosphate and generated P1,P4-Bis(5'-uridyl) tetraphosphate and L-Homocysteic acid, while totally inactivating oxidative-generated metabolites. Ferulic acid also inactivated oxidative-activated pathways, with concomitant reactivation of nucleotide sugars metabolism, starch and sucrose metabolism, and rostenedione metabolism, estrone metabolism, androgen and estrogen metabolism, porphyrin metabolism, and purine metabolism pathways. Taken together, our results indicate the antidiabetic and protective potential of ferulic acid as depicted by its ability to facilitate muscle glucose uptake, inhibit carbohydrate and lipid hydrolyzing enzymes, and modulate oxidative-mediated dysregulated metabolisms. PRACTICAL APPLICATIONS: There have been increasing concerns on the side effects associated with the use of synthetic antidiabetic drug, coupled with their expenses particularly in developing countries. This has necessitated continuous search for alternative treatments especially from natural products having less or no side effects and are readily available. Ferulic acid is among the common phenolics commonly found in fruits and vegetables. In this present study, ferulic acid was able to attenuate oxidative stress, cholinergic dysfunction, and proteolysis in oxidative pancreatic injury, as well as inhibit carbohydrate digesting enzymes. Thus, indicating the ability of the phenolic to protect against complications linked to diabetes. Crops rich in ferulic acid maybe beneficial in managing this disease.

Nonalcoholic Fatty Pancreas Disease: Role in Metabolic Syndrome, "Prediabetes," Diabetes and Atherosclerosis.

Fat accumulation in the pancreas associated with obesity and the metabolic syndrome (MetS) has been defined as "non-alcoholic fatty pancreas disease" (NAFPD). The aim of this review is to describe the association of NAFPD with obesity, MetS, type 2 diabetes mellitus (T2DM) and atherosclerosis and also increase awareness regarding NAFPD. Various methods are used for the detection and quantification of pancreatic fat accumulation that may play a significant role in the differences that have been observed in the prevalence of NAFPD. Endoscopic ultrasound provides detailed images of the pancreas and its use is expected to increase in the future. Obesity and MetS have been recognized as NAFPD risk factors. NAFPD is strongly associated with non-alcoholic fatty liver disease (NAFLD) and it seems that the presence of both may be related with aggravation of NAFLD. A role of NAFPD in the development of "prediabetes" and T2DM has also been suggested by most human studies. Accumulation of fat in pancreatic tissue possibly initiates a vicious cycle of beta-cell deterioration and further pancreatic fat accumulation. Additionally, some evidence indicates a correlation between NAFPD and atherosclerotic markers (e.g., carotid intima-media thickness). Weight loss and bariatric surgery decreases pancreatic triglyceride content but pharmacologic treatments for NAFPD have not been evaluated in specifically designed studies. Hence, NAFPD is a marker of local fat accumulation possibly associated with beta-cell function impairment, carbohydrate metabolism disorders and atherosclerosis.

Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases: Workshop Proceedings.

ABSTRACT: The "Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases" Workshop was a 1.5-day scientific conference at the National Institutes of Health (Bethesda, MD) that engaged clinical and basic science investigators interested in diseases of the pancreas. This report summarizes the workshop proceedings. The goal of the workshop was to forge connections and identify gaps in knowledge that could guide future research directions. Presentations were segregated into 6 major themes, including (a) Pancreas Anatomy and Physiology; (b) Diabetes in the Setting of Exocrine Disease; (c) Metabolic Influences on the Exocrine Pancreas; (d) Genetic Drivers of Pancreatic Diseases; (e) Tools for Integrated Pancreatic Analysis; and (f) Implications of Exocrine-Endocrine Crosstalk. For each theme, there were multiple presentations followed by panel discussions on specific topics relevant to each area of research; these are summarized herein. Significantly, the discussions resulted in the identification of research gaps and opportunities for the field to address. In general, it was concluded that as a pancreas research community, we must more thoughtfully integrate our current knowledge of the normal physiology as well as the disease mechanisms that underlie endocrine and exocrine disorders so that there is a better understanding of the interplay between these compartments.

Association between pancreatic fibrosis and development of pancreoprivic diabetes after pancreaticoduodenectomy.

This study investigated the correlation between pancreatic fibrosis (PF) and development of pancreoprivic diabetes after pancreaticoduodenectomy (PD). Ninety-five patients who underwent PD at Gangnam Severance Hospital between 2014 and 2017 were enrolled. PF grade was evaluated with alpha-smooth muscle actin (SMA) and Masson's trichrome (TRC) staining. New-onset pancreoprivic diabetes and recurrence of disease were evaluated using fasting blood glucose measurement and radiography taken at 3-month intervals. Sixty-one patients did not have preoperative diabetes, however, 40 (65.6%) patients developed pancreoprivic diabetes after PD. High-grade PF was more common in the diabetes group than in the normal group (SMA, 42.5% vs. 28.6%, P = 0.747; TRC, 47.5% vs. 28.6%, P = 0.361). The 1-year cumulative incidence of hyperglycemia/pancreoprivic diabetes was higher with high-grade PF than low-grade PF (SMA, 94.4% vs. 73.0%, P = 0.027; TRC, 89.3% vs. 75.0%, P = 0.074). The SMA-TRC combined high-grade group had a higher proportion of primary pancreatic disease than the combined low-grade group (90.0% vs. 37.5%, P = 0.001). The 5-year disease-free survival of patients with pancreatic cancer was worse with high-grade PF than low-grade PF (SMA, 24.5% vs. 66.3%, P = 0.026; TRC, 23.6% vs. 58.4%, P = 0.047). In conclusion, patients with severe PF are more likely to develop pancreoprivic diabetes after PD and have worse disease-free survival.

Fatty Pancreas Represents a Risk Factor for Acute Pancreatitis: A Pilot Study.

OBJECTIVES: Fatty pancreas (FP), previously believed to be without clinical significance, recently has been shown to be associated with comorbid diseases. We aimed to explore whether FP predispose to acute pancreatitis. METHODS: Patients who underwent endoscopic ultrasound for hepatobiliary indications were included. Patients with pathological pancreato-biliary findings other than FP were excluded. The cohort was divided into patients with a history of pancreatitis (within 6 months of endoscopic ultrasound, group A) and patients without (group B). RESULTS: Overall, 189 patients were included. Sixty-one (32.3%) patients were in group A, and 128 (67.7%) patients were in group B. The average age in group A was 55.5 (standard deviation, 17.7) versus 58.5 (standard deviation, 13.5) in group B. The prevalence of FP in group A (37.7%) was higher compared with group B (4.7%) (P = 0.001). On univariate analysis, FP showed significant correlation with a history of acute pancreatitis [odds ratio (OR), 5.14, P = 0.006] and hyperlipidemia (OR, 4.19; P = 0.002). On multivariate analysis, FP remained significantly associated with a history of acute pancreatitis after stratification for obesity and hyperlipidemia (OR, 10.78; 95% confidence interval, 3.75-30.89; P < 0.0001). CONCLUSIONS: Fatty pancreas was associated with acute pancreatitis. Clinicians should be aware of this association.

Pancreas deficiency modifies bone development in the ovine fetus near term.

Hormones have an important role in the regulation of fetal growth and development, especially in response to nutrient availability in utero. Using micro-CT and an electromagnetic three-point bend test, this study examined the effect of pancreas removal at 0.8 fraction of gestation on the developing bone structure and mechanical strength in fetal sheep. When fetuses were studied at 10 and 25 days after surgery, pancreatectomy caused hypoinsulinaemia, hyperglycaemia and growth retardation which was associated with low plasma concentrations of leptin and a marker of osteoclast activity and collagen degradation. In pancreatectomized fetuses compared to control fetuses, limb lengths were shorter, and trabecular (Tb) bone in the metatarsi showed greater bone volume fraction, Tb thickness, degree of anisotropy and porosity, and lower fractional bone surface area and Tb spacing. Mechanical strength testing showed that pancreas deficiency was associated with increased stiffness and a greater maximal weight load at fracture in a subset of fetuses studied near term. Overall, pancreas deficiency in utero slowed the growth of the fetal skeleton and adapted the developing bone to generate a more compact and connected structure. Maintenance of bone strength in growth-retarded limbs is especially important in a precocial species in preparation for skeletal loading and locomotion at birth.

Stem/progenitor cells in normal physiology and disease of the pancreas.

Though embryonic pancreas progenitors are well characterised, the existence of stem/progenitor cells in the postnatal mammalian pancreas has been long debated, mainly due to contradicting results on regeneration after injury or disease in mice. Despite these controversies, sequencing advancements combined with lineage tracing and organoid technologies indicate that homeostatic and trigger-induced regenerative responses in mice could occur. The presence of putative progenitor cells in the adult pancreas has been proposed during homeostasis and upon different stress challenges such as inflammation, tissue damage and oncogenic stress. More recently, single cell transcriptomics has revealed a remarkable heterogeneity in all pancreas cell types, with some cells showing the signature of potential progenitors. In this review we provide an overview on embryonic and putative adult pancreas progenitors in homeostasis and disease, with special emphasis on in vitro culture systems and scRNA-seq technology as tools to address the progenitor nature of different pancreatic cells.

Diagnostic value of IMP3 and p53 immunohistochemical staining in EUS-guided fine-needle aspiration for solid pancreatic tumors.

We previously identified insulin-like growth factor-II messenger ribonucleic acid-binding protein 3 (IMP3) as a valuable marker to distinguish malignant from benign lesions in pancreatic solid masses. The aim of this prospective study was to evaluate the usefulness of IMP3 and p53 immunohistochemical staining in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) samples for pancreatic solid masses. The study recruited 90 consecutive patients with pancreatic masses, including 62 pancreatic ductal adenocarcinomas (PDACs), 11 benign tumors, and 17 other tumors, who underwent EUS-FNA, and conducted IMP3 and p53 immunohistochemical staining. The main outcome measurement was improved diagnostic utility using IMP3 and p53 immunohistochemical staining. IMP3 and p53 expressions were detected in 60.8% and 49.4% of malignant lesions, 69.4% and 58.1% of PDACs, and 0% of benign lesions, respectively. In PDAC and benign tumors, the use of IMP3 and/or p53 immunostaining increased the sensitivity of cytohistological analysis from 88.7 to 93.5%, although the difference was not statistically significant. The sensitivity of histological analysis combined with that of IMP3 staining was 91.9%, which was significantly greater than that of histology alone (80.6%). The use of IMP3 and p53 immunohistochemical staining did not significantly improve the sensitivity of cytohistological analysis; however, IMP3 staining may be helpful for the histological analysis of malignant pancreatic tumors.

Progressive endoplasmic reticulum stress over time due to human insulin gene mutation contributes to pancreatic beta cell dysfunction.

AIMS/HYPOTHESIS: We studied the effects of heterozygous human INS gene mutations on insulin secretion, endoplasmic reticulum (ER) stress and other mechanisms in both MIN6 and human induced pluripotent stem cells (hiPSC)-derived beta-like cells, as well as the effects of prolonged overexpression of mutant human INS in MIN6 cells. METHODS: We modelled the structure of mutant C109Y and G32V proinsulin computationally to examine the in silico effects. We then overexpressed either wild-type (WT), mutant (C109Y or G32V), or both WT and mutant human preproinsulin in MIN6 cells, both transiently and stably over several weeks. We measured the levels of human and rodent insulin secreted, and examined the transcript and protein levels of several ER stress and apoptotic markers. We also reprogrammed human donor fibroblasts heterozygous for the C109Y mutation into hiPSCs and differentiated these into pancreatic beta-like cells, which were subjected to single-cell RNA-sequencing and transcript and protein analyses for ER stress and apoptotic markers. RESULTS: The computational modelling studies, and short-term and long-term expression studies in beta cells, revealed the presence of ER stress, organelle changes and insulin processing defects, resulting in a decreased amount of insulin secreted but not the ability to secrete insulin. By 9 weeks of expression of mutant human INS, dominant-negative effects of mutant INS were evident and beta cell insulin secretory capacity declined. INS+/C109Y patient-derived beta-like cells and single-cell RNA-sequencing analyses then revealed compensatory upregulation in genes involved in insulin secretion, processing and inflammatory response. CONCLUSIONS/INTERPRETATION: The results provide deeper insights into the mechanisms of beta cell failure during INS mutation-mediated diabetes disease progression. Decreasing spliced X-box binding protein 1 (sXBP1) or inflammatory response could be avenues to restore the function of the remaining WT INS allele.