Mouse Pancreas Research Articles

Effects of Excessive High-fructose Corn Syrup Drink Intake in Middle-aged Mice.

The global prevalence of type 2 diabetes (T2D) continues to increase, necessitating the need for understanding the causes of its development. The widespread use of high-fructose corn syrup (HFCS) in drinks and diets is suspected to play a role in metabolic disorders. Although many studies have reported on the effects of excessive HFCS and excessive energy intakes in middle-aged individuals, few have focused on energy restriction. This study aimed to investigate the effects of excessive HFCS drink intake under energy restriction on developing T2D in early middle-aged mice. Early middle-aged mice were divided in HFCS and control groups; they were provided either 10% HFCS water or deionized water ad libitum for 12 weeks, respectively. Total energy intake was controlled using a standard rodent diet. Oral glucose tolerance test (OGTT), insulin tolerance test (ITT), tissue weight measurements, serum parameter analyses, and mRNA expression assessments were performed. No increase in body and adipose tissue weight was observed with excessive HFCS intake under energy restriction. Moreover, serum lipid parameters did not differ from those of controls. However, in the OGTT and ITT, the HFCS group showed higher blood glucose levels than the control group. Moreover, the pancreatic weight and insulin II mRNA expression were reduced. The excessive HFCS drink intake under energy restriction did not induce obesity; however, it induced impaired glucose tolerance, indicating its negative effects on the pancreas in early middle-aged mice. When translated in human physiology, our results show that even if one does not become obese, excessive HFCS may affect the overall metabolic mechanism; these effects may vary depending on age.

Integrated analysis of genes shared between type 2 diabetes mellitus and osteoporosis.

The relationship between type 2 diabetes mellitus (T2DM) and osteoporosis (OP) has been widely recognized in recent years, but the mechanism of interaction remains unknown. The aim of this study was to investigate the genetic features and signaling pathways that are shared between T2DM and OP. We analyzed the GSE76894 and GSE76895 datasets for T2DM and GSE56815 and GSE7429 for OP from the Gene Expression Omnibus (GEO) database to identify shared genes in T2DM and OP, and we constructed coexpression networks based on weighted gene coexpression network analysis (WGCNA). Shared genes were then further analyzed for functional pathway enrichment. We selected the best common biomarkers using the least absolute shrinkage and selection operator (LASSO) algorithm and validated the common biomarkers, followed by RT-PCR, immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay (ELISA) to validate the expression of these hub genes in T2DM and OP mouse models and patients. We found 8,506 and 2,030 DEGs in T2DM and OP, respectively. Four modules were identified as significant for T2DM and OP using WGCNA. A total of 19 genes overlapped with the strongest positive and negative modules of T2DM and OP. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed these genes may be involved in pantothenate and CoA biosynthesis and the glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and renin-angiotensin system signaling pathway. The LASSO algorithm calculates the six optimal common biomarkers. RT-PCR results show that LTB, TPBG, and VNN1 were upregulated in T2DM and OP. Immunofluorescence and Western blot show that VNN1 is upregulated in the pancreas and bones of T2DM model mice and osteoporosis model mice. Similarly, the level of VNN1 in the sera of patients with T2DM, OP, and T2DM and OP was higher than that in the healthy group. Based on the WGCNA and LASSO algorithms, we identified genes and pathways that were shared between T2DM and OP. Both pantothenate and CoA biosynthesis and the glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and renin-angiotensin systems may be associated with the pathogenesis of T2DM and OP. Moreover, VNN1 may be a potential diagnostic marker for patients with T2DM complicated by OP. This study provides a new perspective for the systematic study of possible mechanisms of combined OP and T2DM.

Anti-Hyperglycemic Effect of the Brown Slime Cap Mushroom Chroogomphus rutilus (Agaricomycetes) Crude Polysaccharide In Vitro and In Vivo.

The prevalence of diabetes is increasing worldwide, and it is very important to study new hypoglycemic active substances. In this study, we investigated the hypoglycemic effect of Chroogomphus rutilus crude polysaccharide (CRCP) in HepG2 cells and streptozotocin-induced diabetic mice. A glucose consumption experiment conducted in HepG2 cells demonstrated the in vitro hypoglycemic activity of CRCP. Furthermore, CRCP exhibited significant hypoglycemic effects and effectively ameliorated insulin resistance in insulin resistant HepG2 cells. In high-fat diet and streptozotocin-induced diabetic mice, after 4 weeks of CRCP administration, fasting blood glucose, fasting serum insulin, triglyceride, total cholesterol, low-density lipoprotein cholesterol, glutamate transaminase, alanine transaminase, and insulin resistance index significantly decreased, while high-density lipoprotein cholesterol and insulin sensitivity index (ISI) were markedly increased. Moreover, hematoxylin-eosin (HE) staining and immunofluorescence labeling of tissue sections indicated that CRCP attenuated the pathological damage of liver and pancreas in diabetic mice. These results indicate that CRCP is a potential hypoglycemic agent.

Ehmt2 inactivation in pancreatic epithelial cells shapes the transcriptional landscape and inflammation response of the whole pancreas.

Introduction: The Euchromatic Histone Methyl Transferase Protein 2 (EHMT2), also known as G9a, deposits transcriptionally repressive chromatin marks that play pivotal roles in the maturation and homeostasis of multiple organs. Recently, we have shown that Ehmt2 inactivation in the mouse pancreas alters growth and immune gene expression networks, antagonizing Kras-mediated pancreatic cancer initiation and promotion. Here, we elucidate the essential role of Ehmt2 in maintaining a transcriptional landscape that protects organs from inflammation. Methods: Comparative RNA-seq studies between normal postnatal and young adult pancreatic tissue from Ehmt2 conditional knockout animals (Ehmt2 fl/fl ) targeted to the exocrine pancreatic epithelial cells (Pdx1-Cre and P48 Cre/+ ), reveal alterations in gene expression networks in the whole organ related to injury-inflammation-repair, suggesting an increased predisposition to damage. Thus, we induced an inflammation repair response in the Ehmt2 fl/fl pancreas and used a data science-based approach to integrate RNA-seq-derived pathways and networks, deconvolution digital cytology, and spatial transcriptomics. We also analyzed the tissue response to damage at the morphological, biochemical, and molecular pathology levels. Results and discussion: The Ehmt2 fl/fl pancreas displays an enhanced injury-inflammation-repair response, offering insights into fundamental molecular and cellular mechanisms involved in this process. More importantly, these data show that conditional Ehmt2 inactivation in exocrine cells reprograms the local environment to recruit mesenchymal and immunological cells needed to mount an increased inflammatory response. Mechanistically, this response is an enhanced injury-inflammation-repair reaction with a small contribution of specific Ehmt2-regulated transcripts. Thus, this new knowledge extends the mechanisms underlying the role of the Ehmt2-mediated pathway in suppressing pancreatic cancer initiation and modulating inflammatory pancreatic diseases.

Cancer-Associated Fibroblast Induces Acinar-to-Ductal Cell Transdifferentiation and Pancreatic Cancer Initiation Via LAMA5/ITGA4 Axis

BACKGROUND & AIMSPancreatic ductal adenocarcinoma (PDAC) is characterized by desmoplastic stroma surrounding most tumors. Activated stromal fibroblasts, namely Cancer-associated fibroblasts (CAFs), play a major role in PDAC progression. Here we analyzed if CAFs influence acinar cells and impact PDAC initiation, namely “Acinar to Ductal Metaplasia” (ADM). ADM connection with PDAC pathophysiology is indicated but not yet established. Hence, we hypothesized that CAF secretome might play a significant role in ADM in PDAC initiation. METHODSMouse and human acinar cell organoids, acinar cells cocultured with CAFs and exposed to CAF-conditioned media (CAF-CM), acinar cell explants, and CAF cocultures, etc., were examined by qRT-PCR, RNA-seq, immunoblotting and confocal microscopy. Data from LC-MS/MS analysis of CAF CM and RNAseq data of acinar cells post-CM exposure were integrated using bioinformatics tools to identify molecular mechanism for CAF-induced ADM. Using confocal microscopy, immunoblotting, and qRT-PCR analysis, we validated the depletion of key signaling axis in cell-line, acinar explant coculture, and mCAFs. RESULTSClose association of acino-ductal (UEA1, Amylase, Ck19) markers and mCAFs (α-SMA) in LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1Cre (KPC) and LSL-KrasG12D/+; Pdx1Cre (KC) autochthonous progression tumor tissue was observed. Caerulein treatment-induced mCAFs increased Ck19 and decreased Amylase in wild-type (WT) and KC pancreas. Likewise, acinar-mCAF cocultures revealed induction of ductal transdifferentiation in cell-line, acinar-organoid, and explant coculture formats in WT and KC mice pancreas. Proteomic and transcriptomic data integration revealed a novel Laminin5/Integrinα4/Stat3 axis responsible for CAF-mediated acinar to ductal cell transdifferentiation. CONCLUSIONResults collectively suggest the first evidence for CAF-influenced acino-ductal phenotypic switchover, thus highlighting tumor micro-environment role in the pancreatic carcinogenesis inception.

Structural Elucidation and Relative Quantification of Fatty Acid Double Bond Positional Isomers in Biological Tissues Enabled by Gas-Phase Charge Inversion Ion/Ion Reactions.

Fatty acids (FAs) contain a vast amount of structural diversity, and differences in fatty acid structure have been associated with various disease states. Accurate identification and characterization of fatty acids is critical to fully understand the biochemical roles these compounds play in disease progression. Conventional tandem mass spectrometry (MS/MS) workflows do not provide sufficient structural information, necessitating alternative dissociation methods. Gas-phase charge inversion ion/ion reactions can be used to alter the ion type subjected to activation to provide improved or complementary structural information. Herein, we have used an ion/ion reaction between fatty acid (FA) anions and magnesium tris-phenanthroline [Mg(Phen)3] dications to promote charge remote fragmentation of carbon-carbon bonds along the fatty acid chain, allowing for localization of carbon-carbon double bond (C=C) positions to successfully differentiate monounsaturated fatty acid isomers. Relative quantification was also performed to obtain the relative abundance of fatty acid isomers in different biological tissues. For example, the relative abundance of FA 18:1 (9) was determined to vary across regions of rat brain, rat kidney, and mouse pancreas, and FA 16:1 (9) was found to have a higher relative abundance in the dermis layer compared to the sebaceous glands in human skin tissue.

Prophylactic and Curative Effect of Boswellia Serrata on Blood Glucose Level and Architecture of Pancreas in Diabetic Mice Induced by Alloxan

Background and objectives. Herbal medicines have gained significant attention from the scientific community for treating and managing diabetes in both developing and developed countries. Boswellia serrata, known for its anti-inflammatory and antioxidant properties, has been historically used to treat various diseases. This study aimed to determine the effect of Boswellia serrata on body weight, blood glucose level, and pancreas architecture in alloxan-induced diabetes in albino mice. Methods. Forty albino male mice, aged 10 to 12 weeks and weighing between 24 and 34 grams, were divided into four groups of ten each. The first group was the negative control group, and the second group was the diabetic positive control group that received 120 mg/kg alloxan intraperitoneally. The third group received a single injection of alloxan at a dose of 120 mg/kg bw and was treated with Boswellia serrata macerated at a dose of 150 mg/kg bw for four weeks. The fourth group received orally Boswellia serrata extract at a dose of 150 mg/kg for two weeks, followed by a single injection of alloxan at a dose of 120 mg/kg, and were left for two weeks. Results. This study found that Boswellia serrata has antidiabetic properties in diabetic mice, as it significantly reduced blood sugar levels compared to the diabetic group. Additionally, histological analyses of the groups treated with B. serrata showed a significant improvement in the harmful effects of alloxan on pancreatic islet cells. Conclusion. Boswellia serrata has shown a notable improvement in the detrimental effect of alloxan on pancreatic islet cells, and its curative effect has been proven to be better than its prophylactic effect. This is supported by the improved blood glucose levels and the histological changes that were more pronounced.

A reversible epigenetic memory of inflammatory injury controls lineage plasticity and tumor initiation in the mouse pancreas

Inflammation is essential to the disruption of tissue homeostasis and can destabilize the identity of lineage-committed epithelial cells. Here, we employ lineage-traced mouse models, single-cell transcriptomic and chromatin analyses, and CUT&TAG to identify an epigenetic memory of inflammatory injury in the pancreatic acinar cell compartment. Despite resolution of pancreatitis, our data show that acinar cells fail to return to their molecular baseline, with retention of elevated chromatin accessibility and H3K4me1 at metaplasia genes, such that memory represents an incomplete cell fate decision. Invivo, we find this epigenetic memory controls lineage plasticity, with diminished metaplasia in response to a second insult but increased tumorigenesis with an oncogenic Kras mutation. The lowered threshold for oncogenic transformation, in turn, can be restored by blockade of MAPK signaling. Together, we define the chromatin dynamics, molecular encoding, and recall of a prolonged epigenetic memory of inflammatory injury that impacts future responses but remains reversible.

Extracellular Vesicle Content Changes Induced by Melatonin Promote Functional Recovery of Pancreatic Beta Cells in Acute Pancreatitis.

Acute pancreatitis is an inflammatory disorder of the pancreas, which causes abnormal activation of immune cells. The macrophages were accumulated in pancreas and infiltrated into islets during the AP process to induce abnormal glucose metabolism. However, the role of macrophages in abnormal glucose metabolism remains understood. Extracellular vesicles act in the regulation of intercellular function, but whether EVs secreted by macrophages contribute to β cell failure and apoptosis in AP is unclear. Based on this, the aim of this study was to reveal the role of macrophages-EVs in AP and develop a treatment for symptoms of hyperglycemia in AP. The AP model was established and treated by various doses of melatonin to analyze the therapeutic effect. The accumulation and polarization of macrophages in the AP pancreas were observed, and the β cells were incubated with pancreatic derived EVs to analyze the role in β cell failure and apoptosis. The results showed that macrophages were recruited and polarized to M1 phenotype macrophages in the pancreas of AP mice, which obtained inflammatory EVs that contained specific miRNAs to induce β cell failure and apoptosis. Then, the EVs derived from M1 macrophages triggered β cell failure and apoptosis. Melatonin prevented polarization of macrophages to the M1 phenotype in vivo, which reduced the secretion of inflammatory EVs, changed the abundance of miRNAs in EVs, and therefore decreased inflammatory EV-mediated β cell failure and apoptosis. Our results demonstrate that similar to 20S proteasome inhibitor MG132, analyses indicated that melatonin prevented degradation of IκBα through the ubiquitylation pathway to restrict p50 subunits to the cytoplasm of macrophages, inhibited activation of the NF-κB pathway to downregulate the transcription of specific miRNAs, and reduced miRNA transport into EVs.

Effects of L-serine on oxidative stress indices and histopathological changes of pancreas in streptozotocin-induced diabetic mice

Effects of L-serine on oxidative stress indices and histopathological changes of pancreas in streptozotocin-induced diabetic mice

Modulation of insulin secretion by RBFOX2-mediated alternative splicing

Insulin secretion is a tightly regulated process that is vital for maintaining blood glucose homeostasis. Although the molecular components of insulin granule trafficking and secretion are well established, how they are regulated to rapidly fine-tune secretion in response to changing environmental conditions is not well characterized. Recent studies have determined that dysregulation of RNA-binding proteins (RBPs) and aberrant mRNA splicing occurs at the onset of diabetes. We demonstrate that the RBP, RBFOX2, is a critical regulator of insulin secretion through the alternative splicing of genes required for insulin granule docking and exocytosis. Conditional mutation of Rbfox2 in the mouse pancreas results in decreased insulin secretion and impaired blood glucose homeostasis. Consistent with defects in secretion, we observe reduced insulin granule docking and corresponding splicing defects in the SNARE complex components. These findings identify an additional mechanism for modulating insulin secretion in both healthy and dysfunctional pancreatic β cells.

Adverse impacts of environmentally relevant PFOS alternatives on mice pancreatic tissues

Perfluorooctane sulfonate (PFOS) alternatives are chemicals that are used to make a range of products. Researchers have found that PFOS alternatives are probably no less toxic than PFOS, which has aroused concern. It has also revealed that the pancreas may be harmed by exposure to PFOS alternatives. However, there is insufficient evidence to demonstrate the toxicity mechanisms of PFOS alternatives. This study demonstrates the adverse effects of three PFOS alternatives on the pancreatic health of mice. After subchronic exposure to PFOS alternatives at environmentally relevant concentrations (800 μg/L perfluorohexanesulfonate, 800 μg/L perfluorobutanesulfonate, and 3 μg/L sodium ρ-perfluorous nonenoxybenzene sulfonate) via drinking water for 6 weeks, toxicity mechanisms were elucidated by examining histopathology, immunity, endoplasmic reticulum stress, 16S rRNA, and short-chain fatty acid targeted metabolomics. Sodium ρ-perfluorous nonenoxybenzene sulfonate significantly increased levels of TNF-α, IL-6, p-PERK, and ATF-4 and decreased the abundance of Akkermansia muciniphila and Lactobacillus reuteri. In addition, the three PFOS alternatives changed the composition of the gut microbiota in mice. Short-chain fatty acids, which are metabolites of the gut microbiota, also significantly decreased. Correlation analysis demonstrates that the alteration of gut microbes is related to the adverse effects on the mice pancreas. Results suggest that the murine pancreas may be toxic endpoints of PFOS alternatives. This study alerts the threats to human health and accelerates the toxicology research of an increasing number of emerging PFOS alternatives.

Pancreas patch grafting to treat type 1 diabetes

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

Pancreas Histology of Hyperglycemia of Mice (Mus musculus L.) After Treatment Basil (Ocimum x africanum Lour.) Leaf Extract and Papaya (Carica papaya L.)

Hyperglycemia is a condition in which the level of glucose in the blood is abnormally high. Hyperglycemia is caused by disturbances in the metabolic system in secreting insulin. Hyperglycemia if left unchecked can cause a disease which is usually called diabetes. Basil (Ocimum x africanum Lour.) and papaya (Carica papaya L.) leaf extracts can reduce blood glucose levels in people with diabetes mellitus because they contain active compounds of flavonoids, alkaloids and tannins which function as anti-diabetics. The aim of this study was to examine the effectiveness of the effects of basil and papaya leaf in affecting the level of islet damage, and repairing pancreatic histological damage in hyperglycemic mice. This study used a completely randomized design with 5 treatment groups and 5 replications. Group K(N) as normal control, group K(+) as positive control, group K (-) as negative control, group P 1 (alloxan induced and treated with ethanol extract of basil leaves 24.5 mg/35g BW mice) 14 days oral) , P 2 group (induced by alloxan and treated with papaya leaf ethanol extract 24.5 mg/35 g BW mice (14 days oral). Data on the level of histological damage to the pancreas of hyperglycemic mice were analyzed using the Kruskal-Wallis method and the Wilcoxon-MannWhitney test at a significant level of 5%. Data histological appearance of the Langerhans were analyzed descriptively.The results showed basil leaf extract and papaya had an effect on the level of damage to the pancreas of mice, basil leaf extract was effective compared to papaya in histological repair of the mice pancreas

Extract and fraction of cashew nut testa ameliorate the hyperglycemic mice induced by Streptozotocin and high-fat diet

Drug strategy is a standard method for treating type 2 diabetes mellitus (T2D), a non-communicable disease with increasing prevalence, which may cause side effects. Therefore, natural compounds with limited adverse effects have come back into vogue for treating T2D. This study aims to evaluate the effects on rehabilitating hyperglycemic mice of cashew nut testa (husk) extract and fraction known as potential bio-substances for improvement in T2D. First, the hyperglycemic mice were induced with a high-fat diet (HFD) for 4 weeks and then were injected with streptozotocin (STZ, dozen for injection was 40 mg/kg/week) for 2 weeks. Next, the confirmed hyperglycemic mice were treated with pioglitazone (HG+PG group), total extract (HG+TE group), and saponin-rich fraction (HG+SRF group) for 3 weeks. Then, the evaluation was based on body mass; blood glucose (BG) level; BG tolerance, lipid profile, pancreatic histology and the expression IRS-1 in the pancreas. The results showed that body mass and BG level significantly increased in hyperglycemic mice. After substance treatment, there was no change in body mass in TE and SRF groups. However, BG level of HG+TE group mice significantly decreased compared to hyperglycemic mice and only BG tolerance of HG+SRF group was improved. Besides, HG+TE and HG+SRF groups modulated the triglyceride, HDL and LDL close to those expressed in normal mice. In addition, histological images of the pancreas revealed the restoration in both HG+TE and HG+SRF groups. Simultaneously, the IRS-1 expression in HG+TE group pancreas was restored to its expression in normal mice. These results demonstrate that the TE and SRF of cashew nut testa could ameliorate BG, lipid profile and pancreatic IRS-1 expression and restore the damaged pancreas and islets in hyperglycemic mice.

Connective tissue mast cells store and release noradrenaline

Mast cells are present in mucosal and connective tissues throughout the body. They synthesize and release a wide variety of bioactive molecules, such as histamine, proteases, and cytokines. In this study, we found that a population of connective tissue mast cells (CTMCs) stores and releases noradrenaline, originating from sympathetic nerves. Noradrenaline-storing cells, not neuronal fibers, were predominantly identified in the connective tissues of the skin, mammary gland, gastrointestinal tract, bronchus, thymus, and pancreas in wild-type mice but were absent in mast cell–deficient W-sash c-kit mutant KitW−sh/W−sh mice. In vitro studies using bone marrow–derived mast cells revealed that extracellular noradrenaline was taken up but not synthesized. Upon ionomycin stimulation, noradrenaline was released. Electron microscopy analyses further suggested that noradrenaline is stored in and released from the secretory granules of mast cells. Finally, we found that noradrenaline-storing CTMCs express organic cation transporter 3 (Oct3), which is also known as an extraneuronal monoamine transporter, SLC22A3. Our findings indicate that mast cells may play a role in regulating noradrenaline concentration by storing and releasing it in somatic tissues.

Growth of B16F10 cells is enhanced in DJ-1-deficiency pancreas

Association between cancer risk and Parkinson's disease is still debated. DJ-1, a Parkinson's disease (PD)-related gene, is encoded by PARK-7 gene and its deficiency causes early-onset PD. In our last studies, it was found that the immunosuppressive microenvironment established in DJ-1 knockout (KO) mice can enhance metastasis of melanoma cells to lungs. Therefore, we wanted to further examine whether there were some niche in other organs of DJ-1-deficiency mouse to facilitate cell growth of tumors. We used in vivo tissue-specific models of tumor growth and in vitro cellular model to verify the hypothesis. We also used protein blot assay, cell-adhesion assay and bioinformatic tools to conduct experiments. In the mouse model of subcutaneous injection, there was no difference on tumor growth between WT and DJ-1 KO mice. Moreover, the results of experimental liver metastasis by intrasplenic injection model showed that there was no difference of nodules number in both mice, but a dramatic enhancement of nodule formation and increased mucin4 levels were found in pancreas of DJ-1 KO mice. In cell cultures, we further found that B16F10 cells indeed tended to adhere well to primary DJ-1-deficiency pancreatic epithelial cells, which had higher protein levels of mucin4. Notably, a human database also showed the inverse relationship in human pancreas between DJ-1 and mucin4, and mucin4 down-regulation can reverse the enhanced cellular adhesion in DJ-1 KO pancreatic epithelial cells. These results indicated that DJ-1 KO pancreatic tissue creating an appropriate microenvironment benefited development of the cancer cells.

Meflin is a marker of pancreatic stellate cells involved in fibrosis and epithelial regeneration in the pancreas.

Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin+ ) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.

Activation of AMPK ameliorates acute severe pancreatitis by suppressing pancreatic acinar cell necroptosis in obese mice models

Obese people with acute pancreatitis (AP) have an increased risk of developing severe acute pancreatitis (SAP), which prolongs the length of hospital stay and increases mortality. Thus, elucidation of the mechanisms through which SAP occurs in obese individuals will provide clues for possible treatment targets. Differences in early events in obese or lean patients with AP have not been conclusively reported. We selected C57BL/6 mice as lean mice models, ob/ob mice or diet induced obese (DIO) mice as obese mice models and then induced experimental AP in mice via injections of caerulein. There were suppressed p-AMPK expressions in the pancreas of obese mice, compared with same-age lean C57BL/6 mice, which were further reduced in AP mice models. Obese AP mice were treated using AICAR, a direct AMPK agonist, which prevented pancreatic damage and cell death, suppressed pancreatic enzyme levels in serum, reduced the areas of fat saponification in the peritoneal cavity, prevented injury in other organs and decreased mice mortality rate. Further assays showed that AICAR activates p-AMPK to stabilize pro-caspase-8. Pro-caspase-8 enhances RIPK3 degradation, inhibits pancreatic acinar cell necroptosis, and downregulates the release of pancreatic enzymes. Thus, activation of AMPK by AICAR alleviates pancreatic acinar cell necroptosis and converts SAP to mild acute pancreatitis in obese mice.

Metal-polyphenol microgels for oral delivery of puerarin to alleviate the onset of diabetes.

Puerarin (Pue) is a naturally bioactive compound with many potential functions in regulating blood glucose and lipid metabolism. However, the low bioavailability and rapid elimination in vivo limit the application of Pue in diabetic treatment. Here, we developed a metal-polyphenol-functionalized microgel to effectively deliver Pue in vivo and eventually alleviate the onset of diabetes. Pue was initially encapsulated in alginate beads through electrospray technology, and further immersed in Fe3+ and tannic acid solution from tannic acid (TA)-iron (Fe) coatings (TF). These constructed Pue@SA-TF microgels exhibited uniform spheres with an average size of 367.89 ± 18.74µm and high encapsulation efficiency of Pue with 61.16 ± 1.39%. In vivo experiments proved that compared with free Pue and microgels without TF coatings, the biological distribution of Pue@SA-TF microgels specifically accumulated in the small intestine, prolonged the retention time of Pue, and achieved a high effectiveness in vivo. Anti-diabetic experimental results showed that Pue@SA-TF microgels significantly improved the levels of blood glucose, blood lipid, and oxidative stress in diabetic mice. Meanwhile, histopathological observations indicated that Pue@SA-TF microgels could significantly alleviate the damage to the liver, kidney, and pancreas in diabetic mice. Our study provided an effective strategy for oral delivery of Pue and achieved high anti-diabetic efficacy.