Search Results (39)

Hyperglycemia during fetal development disturbs extracellular matrix (ECM) synthesis and deposition patterns, which disrupts organogenesis and adult organ function. Although the ECM cooperates in pancreas development, little is known about the effects of hyperglycemia on the pancreatic ECM during development. This study investigates the effect of severe maternal hyperglycemia on ECM composition and endocrine pancreas development in E19.0 mouse fetuses. Deposition patterns of pan-laminin, laminin (alpha 1 and gamma 1 chains) and integrin alpha 3 were evaluated by immunostaining. The proliferative index of islet cells and alpha and beta cell distribution were evaluated by PCNA, glucagon and insulin immunostaining, respectively. Pdx1 and Pax4 expressions were analyzed by RT-qPCR. While for pan-laminin and laminin (alpha1 and gamma1 chains) deposition was weaker in the endocrine pancreas of hyperglycemic mothers’ fetuses, integrin alpha 3 deposition in the basement membrane was increased. The proliferative index of endocrine cells was lower in the hyperglycemic group, while the beta-cell area was increased. In addition, there was a tendency towards lower Pdx1 and increased Pdx4 expression. These data suggest that maternal hyperglycemia alters fetal endocrine pancreas morphogenesis by modifying peri-islet basement membrane molecule patterns, promoting a decrease in endocrine cell proliferation associated with changes in the expression of important growth factors for the beta cells differentiated and the proliferative state. Full article

(Proline3)PP, or (P³)PP, is an enzymatically stable, neuropeptide Y4 receptor (NPY4R)-selective, pancreatic polypeptide (PP) analogue with established weight-lowering and pancreatic islet morphology benefits in obesity-diabetes. In the current study, we now investigate the impact of twice-daily (P³)PP administration (25 nmol/kg) for 11 days on islet cell lineage, using streptozotocin (STZ) diabetic Ins1^Cre/+;Rosa26-eYFP and Glu^CreERT2;Rosa26-eYFP transgenic mice with enhanced yellow fluorescent protein (eYFP) labelling of beta-cell and alpha-cells, respectively. (P³)PP had no obvious impact on body weight or blood glucose levels in STZ-diabetic mice at the dose tested, but did return food intake towards control levels in Ins1^Cre/+;Rosa26-eYFP mice. Notably, pancreatic insulin content was augmented by (P³)PP treatment in both Ins1^Cre/+;Rosa26-eYFP and Glu^CreERT2;Rosa26-eYFP mice, alongside enhanced beta-cell area and reduced alpha-cell area. Beneficial (P³)PP-induced changes on islet morphology were consistently associated with decreased beta-cell apoptosis, while (P³)PP also augmented beta-cell proliferation in Ins1^Cre/+;Rosa26-eYFP mice. Alpha-cell turnover rates were returned towards healthy control levels by (P³)PP intervention in both mouse models. In terms of islet cell lineage, increased transition of alpha- to beta-cells as well as decreased beta- to alpha-cell differentiation were shown to contribute towards the enhancement of beta-cell area in (P³)PP-treated mice. Together these data reveal, for the first time, sustained NPY4R activation positively modulates beta-cell turnover, as well as islet cell plasticity, to help preserve pancreatic islet architecture following STZ-induced metabolic stress. Full article

Probiotics show beneficial effects on diabetes mellitus (DM). If probiotics can secrete the recombinant insulins that may help suppress DM development, then it would likely have very few adverse side effects. To produce insulin analogs in bacteria, recombinant insulin (insulin-CBT1) should be the single-chain insulin (SCI) similar to proinsulin. However, insulin-CBT1 should allow the protein to activate insulin receptors directly without the need for proteolytic cleavage. In this study, we evaluated the effect of the flexible linker peptide on the physical and structural characteristics of insulin-CBT1 compared with commercial insulin (c-insulin). In the results, the linker peptide had marked effects on polarity and structure by increasing the α-helix content (19.3%→25.6%). Furthermore, insulin-CBT1 induced MIN6 proliferation 1.75-fold more than c-insulin, whereas differentiation and glucose uptake rates by 3T3-L1 were 39% and 15% lower, respectively. The biological anti-diabetes properties of insulin-CBT1 were well evaluated compared with c-insulin. Furthermore, we first suggest a special method for oral administration of insulin-CBT 1 without damage to the digestive tract. We developed an insulin-CBT1 delivery system using Pediococcus pentosaceus (PP), which has been reported as a potential bacteria in DM. First, insulin-CBT1 was harbored in pCBT2-24, which verified the expression and secretion vector system of PP. We finally confirmed that PP-insulin-CBT1 successfully secreted insulin-CBT1 proteins to culture media. These results presented herein open up new avenues to developing therapeutic options for DM. Full article

Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are related intestinal L-cell derived secretory products. GLP-1 has been extensively studied in terms of its influence on metabolism, but less attention has been devoted to GLP-2 in this regard. The current study compares the effects of these proglucagon-derived peptides on pancreatic beta-cell function, as well as on glucose tolerance and appetite. The insulin secretory effects of GLP-1 and GLP-2 (10⁻¹²–10⁻⁶ M) were investigated in BRIN-BD11 beta-cells as well as isolated mouse islets, with the impact of test peptides (10 nM) on real-time cytosolic cAMP levels further evaluated in mouse islets. The impact of both peptides (10⁻⁸–10⁻⁶ M) on beta-cell growth and survival was also studied in BRIN BD11 cells. Acute in vivo (peptides administered at 25 nmol/kg) glucose homeostatic and appetite suppressive actions were then examined in healthy mice. GLP-1, but not GLP-2, concentration dependently augmented insulin secretion from BRIN-BD11 cells, with similar observations made in isolated murine islets. In addition, GLP-1 substantially increased [cAMP]_cyt in islet cells and was significantly more prominent than GLP-2 in this regard. Both GLP-1 and GLP-2 promoted beta-cell proliferation and protected against cytokine-induced apoptosis. In overnight fasted healthy mice, as well as mice trained to eat for 3 h per day, the administration of GLP-1 or GLP-2 suppressed appetite. When injected conjointly with glucose, both peptides improved glucose disposal, which was associated with enhanced glucose-stimulated insulin secretion by GLP-1, but not GLP-2. To conclude, the impact of GLP-1 and GLP-2 on insulin secretion is divergent, but the effects of beta-cell signaling and overall health are similar. Moreover, the peripheral administration of either hormone in rodents results in comparable positive effects on blood glucose levels and appetite. Full article

Background: The interaction between cancer cells and cancer-associated fibroblasts (CAFs) is a key determinant of the rapid progression, high invasiveness, and chemoresistance of aggressive desmoplastic cancers such as pancreatic ductal adenocarcinoma (PDAC). Tumor cells are known to reprogram fibroblasts into CAFs by secreting transforming growth factor beta (TGF-β), amongst other cytokines. In turn, CAFs produce soluble factors that promote tumor-cell invasiveness and chemoresistance, including TGF-β itself, which has a major role in myofibroblastic CAFs. Such a high level of complexity has hampered progress toward a clear view of the TGFβ signaling loop between stromal fibroblasts and PDAC cells. Methods: Here, we tackled this issue by using co-culture settings that allow paracrine signaling alone (transwell systems) or paracrine and contact-mediated signaling (3D spheroids). Results: We found that TGF-β is critically involved in the activation of normal human fibroblasts into alpha-smooth muscle actin (α-SMA)-positive CAFs. The TGF-β released by CAFs accounted for the enhanced proliferation and resistance to gemcitabine of PDAC cells. This was accompanied by a partial epithelial-to-mesenchymal transition in PDAC cells, with no increase in their migratory abilities. Nevertheless, 3D heterospheroids comprising PDAC cells and fibroblasts allowed monitoring the pro-invasive effects of CAFs on cancer cells, possibly due to combined paracrine and physical contact-mediated signals. Conclusions: We conclude that TGF-β is only one of the players that mediates the communication between PDAC cells and fibroblasts and controls the acquisition of aggressive phenotypes. Hence, these advanced in vitro models may be exploited to further investigate these events and to design innovative anti-PDAC therapies. Full article

We previously demonstrated that boundary cap neural crest stem cells (BCs) induce the proliferation of beta-cells in vitro, increase survival of pancreatic islets (PIs) in vivo after transplantation, and themselves strongly increase their proliferation capacity after exposure to space conditions. Therefore, we asked if space conditions can induce the proliferation of beta-cells when PIs are alone or together with BCs in free-floating or 3D-printed form. During the MASER 15 sounding rocket experiment, half of the cells were exposed to 6 min of microgravity (µg), whereas another group of cells were kept in 1 g conditions in a centrifuge onboard. The proliferation marker EdU was added to the cells just before the rocket reached µg conditions. The morphological assessment revealed that PIs successfully survived and strongly proliferated, particularly in the free-floating condition, though the fusion of PIs hampered statistical analysis. Proliferation of beta-cells was displayed in 3D-printed islets two weeks after µg exposure, suggesting that the effects of µg may be delayed. Thus, PIs in 3D-printed scaffolds did not fuse, and this preparation is more suitable than free-floating specimens for morphological analysis in µg studies. PIs maintained their increased proliferation capacity for weeks after µg exposure, an effect that may not appear directly, but can emerge after a delay. Full article

Introduction: Crosstalk occurs between nerve and cancer cells. These interactions are important for cancer homeostasis and metabolism. Nerve cells influence the tumor microenvironment (TME) and participate in metastasis through neurogenesis, neural extension, and axonogenesis. We summarized the past and current literature on the interaction between nerves and cancer, with a special focus on pancreatic ductal adenocarcinoma (PDAC), prostate cancer (PCa), and the role of the nerve growth factor (NGF) in cancer. Materials/Methods: We reviewed PubMed and Google Scholar for the relevant literature on the relationship between nerves, neurotrophins, and cancer in general and specifically for both PCa and PDAC. Results: The NGF helped sustain cancer cell proliferation and evade immune defense. It is a neuropeptide involved in neurogenic inflammation through the activation of several cells of the immune system by several proinflammatory cytokines. Both PCa and PDAC employ different strategies to evade immune defense. The prostate is richly innervated by both the sympathetic and parasympathetic nerves, which helps in both growth control and homeostasis. Newly formed autonomic nerve fibers grow into cancer cells and contribute to cancer initiation and progression through the activation of β-adrenergic and muscarinic cholinergic signaling. Surgical or chemical sympathectomy prevents the development of prostate cancer. Beta-blockers have a high therapeutic potential for cancer, although current clinical data have been contradictory. With a better understanding of the beta-receptors, one could identify specific receptors that could have an effect on prostate cancer development or act as therapeutic agents. Conclusion: The bidirectional crosstalk between the nervous system and cancer cells has emerged as a crucial regulator of cancer and its microenvironment. Denervation has been shown to be promising in vitro and in animal models. Additionally, there is a potential relationship between cancer and psychosocial biology through neurotransmitters and neurotrophins. Full article

Background & Aims: Acinar-to-ductal metaplasia (ADM) serves as a precursor event in the development of pancreatic ductal adenocarcinoma (PDAC) upon constitutive environmental and genetical stress. While the role of ADM in PDAC progression has been established, the molecular mechanisms underlying human ADM remain elusive. We previously demonstrated the induction of ADM in human acinar cells through the transforming growth factor beta (TGFβ) signaling pathway. We aim to investigate the interaction between TGFβ and Hippo pathways in mediating ADM. Methods: RNA-sequencing was conducted on sorted normal primary human acinar, ductal, and AD (acinar cells that have undergone ADM) cells. ATAC-seq analysis was utilized to reveal the chromatin accessibility in these three cell types. ChIP-Seq of YAP1, SMAD4, and H3K27ac was performed to identify the gene targets of YAP1 and SMAD4. The role of YAP1/TAZ in ADM-driven cell proliferation, as well as in oncogenic KRAS driven proliferation, was assessed using sphere formation assay. Results: AD cells have a unique transcription profile, with upregulated genes in open chromatin states in acinar cells. YAP1 and SMAD4 co-occupy the loci of ADM-related genes, including PROM1, HES1, and MMP7, co-regulating biological functions such as cell adhesion, cell migration, and inflammation. Overexpression of YAP1/TAZ promoted acinar cell proliferation but still required the TGFβ pathway. YAP1/TAZ were also crucial for TGFβ-induced sphere formation and were necessary for KRAS-induced proliferation. Conclusions: Our study reveals the intricate transition between acinar and AD states in human pancreatic tissues. It unveils the complex interaction between the Hippo and TGF-β pathways during ADM, highlighting the pivotal role of YAP1/TAZ and SMAD4 in PDAC initiation. Full article

Background: Epidemiological clinical reports have shown an association between iodine excess with diabetes mellitus type 2 and higher blood glucose. However, the relationship between iodine, the pancreas, adipose tissue, and glucose transport is unclear. The goal of this study was to analyze the effect of iodine concentrations (in Lugol solution) on glucose transport, insulin secretion, and its cytotoxic effects in mature 3T3-L1 adipocytes and pancreatic beta-TC-6 cells. Methods: Fibroblast 3T3-L1, mature adipocytes, and pancreatic beta-TC-6 cells were treated with 1 to 1000 µM of Lugol (molecular iodine dissolved in potassium iodide) for 30 min to 24 h for an MTT proliferation assay. Then, glucose uptake was measured with the fluorescent analog 2-NBDG, insulin receptor, Akt protein, p-Akt (ser-473), PPAR-gamma, and Glut4 by immunoblot; furthermore, insulin, alpha-amylase, oxidative stress, and caspase-3 activation were measured by colorimetric methods and the expression of markers of the apoptotic pathway at the RNAm level by real-time PCR. Results: Low concentrations of Lugol significantly induce insulin secretion and glucose uptake in pancreatic beta-TC-6 cells, and in adipose cells, iodine-induced glucose uptake depends on the serine-473 phosphorylation of Akt (p-Akt) and Glut4. Higher doses of Lugol lead to cell growth inhibition, oxidative stress, and cellular apoptosis dependent on PPAR-gamma, Bax mRNA expression, and caspase-3 activation in pancreatic beta-TC-6 cells. Conclusions: Iodine could influence glucose metabolism in mature adipocytes and insulin secretion in pancreatic beta cells, but excessive levels may cause cytotoxic damage to pancreatic beta cells. Full article

Type 2 diabetes (T2D) is characterized by pancreatic beta-cell dysfunction, increased cell death and loss of beta-cell mass despite chronic treatment. Consequently, there has been growing interest in developing beta cell-centered therapies. Beta-cell regeneration is mediated by augmented beta-cell proliferation, transdifferentiation of other islet cell types to functional beta-like cells or the reprograming of beta-cell progenitors into fully differentiated beta cells. This mediation is orchestrated by beta-cell differentiation transcription factors and the regulation of the cell cycle machinery. This review investigates the beta-cell regenerative potential of antidiabetic plant extracts and phytochemicals. Various preclinical studies, including in vitro, in vivo and ex vivo studies, are highlighted. Further, the potential regenerative mechanisms and the intra and extracellular mediators that are of significance are discussed. Also, the potential of phytochemicals to translate into regenerative therapies for T2D patients is highlighted, and some suggestions regarding future perspectives are made. Full article

Three-dimensional matrices are a new strategy used to tackle type I diabetes, a chronic metabolic disease characterized by the destruction of beta pancreatic cells. Type I collagen is an abundant extracellular matrix (ECM), a component that has been used to support cell growth. However, pure collagen possesses some difficulties, including a low stiffness and strength and a high susceptibility to cell-mediated contraction. Therefore, we developed a collagen hydrogel with a poly (ethylene glycol) diacrylate (PEGDA) interpenetrating network (IPN), functionalized with vascular endothelial growth factor (VEGF) to mimic the pancreatic environment for the sustenance of beta pancreatic cells. We analyzed the physicochemical characteristics of the hydrogels and found that they were successfully synthesized. The mechanical behavior of the hydrogels improved with the addition of VEGF, and the swelling degree and the degradation were stable over time. In addition, it was found that 5 ng/mL VEGF-functionalized collagen/PEGDA IPN hydrogels sustained and enhanced the viability, proliferation, respiratory capacity, and functionality of beta pancreatic cells. Hence, this is a potential candidate for future preclinical evaluation, which may be favorable for diabetes treatment. Full article

Long non-coding RNAs (lncRNAs) have emerged as a significant player in various cancers, including pancreatic cancer. However, how lncRNAs are aberrantly expressed in cancers is largely unknown. We hypothesized that lncRNAs would be regulated by signaling pathways and contribute to malignant phenotypes of cancer. In this study, to understand the significance of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK), which is a major aberrant signaling pathway in pancreatic cancer, for the expression of lncRNAs, we performed comparative transcriptome analyses between pancreatic cancer cell lines with or without activation of MAPK. We identified 45 lncRNAs presumably associated with MAPK in pancreatic cancer cells; among these, LINC00941 was consistently upregulated by MAPK. The immediate genomic upstream region flanking LINC00941 was identified as a promoter region, the activity of which was found to be preferentially associated with MAPK activity via ETS-1 binding site. LINC00941 promoted cell proliferation in vitro. Moreover, TCGA data analysis indicated that high expression of LINC00941 was associated with poor prognosis of patients with pancreatic cancer. Transcriptomes comparing transcriptions between cells with and without LINC00941 knockdown revealed 3229 differentially expressed genes involved in 44 biological processes, including the glycoprotein biosynthetic process, beta-catenin-TCF complex assembly, and histone modification. These results indicate that MAPK mediates the aberrant expression of lncRNAs. LINC00941 is the lncRNA by MAPK most consistently promoted, and is implicated in the dismal prognosis of pancreatic cancer. MAPK-associated lncRNAs may play pivotal roles in malignant phenotypes of pancreatic cancer, and as such might represent both potentially valid therapeutic targets and diagnostic biomarkers. Full article

Acute pancreatitis (AP) is an inflammatory disease of the pancreas. A growing number of studies have shown that long noncoding RNAs (lncRNAs) play an important role in AP progression. Here, we aimed to elucidate the role of Small Nucleolar RNA Host Gene 11(SNHG11) and its underlying molecular mechanisms behind AP progression. The in vivo and in vitro AP cell models were established by retrograde injection of sodium taurocholate and caerulein stimulation into AR42J cells and HPDE6-C7 cells, respectively. A bioinformatics website predicted the relationship between SNHG11, miR-7-5p, and Phospholipase C Beta 1(PLCB1) and validated it with a dual-luciferase reporter assay and an RNA immunoprecipitation (RIP) assay. AR42J cells and HPDE6-C7 cells were transfected with an overexpression of plasmids or shRNA to investigate the effects of the SNHG11/miR-7-5p/PLCB1 axis on cell proliferation and apoptosis, inflammatory cytokine secretion, and acute pancreatitis. Low expression of SNHG11 and PLCB1 and high expression of miR-7-5p were observed in AP pancreatic tissue and AP cell models. SNHG11 overexpression inhibited apoptosis and inflammatory responses induced by caerulein. Simultaneously, we discovered that SNHG11 regulates PLCB1 expression by sponging miR-7-5p. PLCB1 overexpression abrogated inflammatory damage exacerbated by miR-7-5p enrichment. In addition, the SNHG11/miR-7-5p/PLCB1 axis could be involved in caerulein-induced inflammatory injury by participating in the p38MAPK signaling pathway. The overexpressed SNHG11/miR-7-5p/PLCB1 axis can inhibit AP progression by participating in the p38MAPK signaling pathway, thereby providing a potential therapeutic target and therapeutic direction for AP therapy. Full article

During mouse pregnancy placental lactogens stimulate prolactin receptors on pancreatic islet beta cells to induce expression of the tryptophan hydroxylase Tph1, resulting in the synthesis and secretion of serotonin. Presently, the functional relevance of this phenomenon is unclear. One hypothesis is that serotonin-induced activation of 5-HT_2B receptors on beta cells stimulates beta cell proliferation during pregnancy. We tested this hypothesis via three different mouse models: (i) total Tph1KO mice, (ii) 129P2/OlaHsd mice, which are incompetent to upregulate islet Tph1 during pregnancy, whereas Tph1 is normally expressed in the intestine, mammary glands, and placenta, and (iii) Htr2b-deficient mice. We observed normal pregnancy-induced levels of beta cell proliferation in total Tph1KO mice, 129P2/OlaHsd mice, and in Htr2b^−/− mice. The three studied mouse models indicate that islet serotonin production and its signaling via 5-HT_2B receptors are not required for the wave of beta cell proliferation that occurs during normal mouse pregnancy. Full article

Glycogen synthase kinase 3 beta (GSK-3β) is a serine/threonine protein kinase involved in multiple normal and pathological cell functions, including cell signalling and metabolism. GSK-3β is highly expressed in the onset and progression of multiple cancers with strong involvement in the regulation of proliferation, apoptosis, and chemoresistance. Multiple studies showed pro- and anti-cancer roles of GSK-3β creating confusion about the benefit of targeting GSK-3β for treating cancer. In this mini-review, we focus on the role of GSK-3β in pancreatic cancer. We demonstrate that the proposed anti-cancer roles of GSK-3β are not relevant to pancreatic cancer, and we argue why GSK-3β is, indeed, a very promising therapeutic target in pancreatic cancer. Full article