scholarly journals Pancreas-specific miR-216a regulates proliferation and endocrine and exocrine cell function in vivo

2019 ◽  
Author(s):  
Suheda Erener ◽  
Cara E. Ellis ◽  
Adam Ramzy ◽  
Maria M. Glavas ◽  
Shannon O’Dwyer ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cell Function ◽  
Cell Mass ◽  
Biological Processes ◽  
Exocrine Cells ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Cancer Line ◽  
Islet Size

AbstractPancreas is a vital organ composed of exocrine and endocrine cells that aid digestion of food and regulate blood glucose levels. Perturbations in the function of pancreatic cells leads to the development of life-burdening and/or threatening diseases such as diabetes and pancreatic cancer. Thus, it is critical to understand the molecular check-points that maintain normal pancreas physiology. MicroRNAs (miRNAs) are small non-coding RNAs involved in regulating gene expression in normal and diseased tissues. Several miRNAs have tissue-specific patterns consistent with crucial functions in many biological processes. Yet, there is limited knowledge about the role of pancreas-specific miRNAs in pancreatic pathologies. Here, we report that miR-216a is a conserved, pancreas-specific miRNA that is expressed in both endocrine and exocrine cells. Deletion of miR-216a in mice leads to reduced β-cell mass and a reduction in islet size under both chow and high-fat diet feeding conditions. We show that inhibition of miR-216a increases apoptosis and decreases cell proliferation in β- and exocrine cells. Smad7 is upregulated in miR-216a deficient islets and cell cycle and proliferation are among the most significantly regulated biological processes in miR-216 knockout pancreata. Re-introduction of miR-216a in the pancreatic cancer line, PANC-1, increases cell migration more than 2-fold. In vivo, deletion of miR-216a in the pancreatic cancer prone mouse line KrasG12D;Ptf1aCreER inhibits the propensity of pancreatic cancer precursor lesions. Our study identifies miR-216a as an important pancreas-specific miRNA which may have implications for both diabetes and pancreatic cancer.

scholarly journals Loss of β-cell identity and diabetic phenotype in mice caused by disruption of CNOT3-dependent mRNA deadenylation

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Dina Mostafa ◽  
Akiko Yanagiya ◽  
Eleni Georgiadou ◽  
Yibo Wu ◽  
Theodoros Stylianides ◽  
...  
Keyword(s):  
Cell Function ◽  
Cell Mass ◽  
Cell Maturation ◽  
Β Cells ◽  
Β Cell ◽  
Cell Identity ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Β Cell Function ◽  
And Function

AbstractPancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Defects in β-cell function lead to hyperglycemia and diabetes mellitus. Here, we show that CNOT3, a CCR4–NOT deadenylase complex subunit, is dysregulated in islets in diabetic db/db mice, and that it is essential for murine β cell maturation and identity. Mice with β cell-specific Cnot3 deletion (Cnot3βKO) exhibit impaired glucose tolerance, decreased β cell mass, and they gradually develop diabetes. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes, and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increased expression of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.

scholarly journals Follow-up of GK rats during prediabetes highlights increased insulin action and fat deposition despite low insulin secretion

2008 ◽  
Vol 294 (1) ◽  
pp. E168-E175 ◽  
Author(s):  
Jamileh Movassat ◽  
Danièle Bailbé ◽  
Cécile Lubrano-Berthelier ◽  
Françoise Picarel-Blanchot ◽  
Eric Bertin ◽  
...  
Keyword(s):  
Body Composition ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Cell Function ◽  
Cell Mass ◽  
The Body ◽  
Whole Body ◽  
Β Cell ◽  
Gk Rats

The adult Goto-Kakizaki (GK) rat is characterized by impaired glucose-induced insulin secretion in vivo and in vitro, decreased β-cell mass, decreased insulin sensitivity in the liver, and moderate insulin resistance in muscles and adipose tissue. GK rats do not exhibit basal hyperglycemia during the first 3 wk after birth and therefore could be considered prediabetic during this period. Our aim was to identify the initial pathophysiological changes occurring during the prediabetes period in this model of type 2 diabetes (T2DM). To address this, we investigated β-cell function, insulin sensitivity, and body composition in normoglycemic prediabetic GK rats. Our results revealed that the in vivo secretory response of GK β-cells to glucose is markedly reduced and the whole body insulin sensitivity is increased in the prediabetic GK rats in vivo. Moreover, the body composition of suckling GK rats is altered compared with age-matched Wistar rats, with an increase of the number of adipocytes before weaning despite a decreased body weight and lean mass in the GK rats. None of these changes appeared to be due to the postnatal nutritional environment of GK pups as demonstrated by cross-fostering GK pups with nondiabetic Wistar dams. In conclusion, in the GK model of T2DM, β-cell dysfunction associated with increased insulin sensitivity and the alteration of body composition are proximal events that might contribute to the establishment of overt diabetes in adult GK rats.

scholarly journals From Theory to Clinical Practice in the Use of GLP-1 Receptor Agonists and DPP-4 Inhibitors Therapy

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Ilaria Dicembrini ◽  
Laura Pala ◽  
Carlo Maria Rotella
Keyword(s):  
Cell Function ◽  
Lifestyle Modification ◽  
Cell Mass ◽  
Beta Cell Mass ◽  
Minimal Risk ◽  
Dipeptidyl Peptidase 4 ◽  
Receptor Agonists ◽  
Dipeptidyl Peptidase 4 Inhibitors

Promoting long-term adherence to lifestyle modification and choice of antidiabetic agent with low hypoglycemia risk profile and positive weight profile could be the most effective strategy in achieving sustained glycemic control and in reducing comorbidities. From this perspective, vast interest has been generated by glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 inhibitors (DPP-4i). In this review our ten-year clinical and laboratory experience byin vitroandin vivostudies is reported. Herein, we reviewed available data on the efficacy and safety profile of GLP-1 receptor agonists and DPP-4i. The introduction of incretin hormone-based therapies represents a novel therapeutic strategy, because these drugs not only improve glycemia with minimal risk of hypoglycemia but also have other extraglycemic beneficial effects. In clinical studies, both GLP-1 receptor agonists and DPP-4i, improveβcell function indexes. All these agents showed trophic effects on beta-cell mass in animal studies. The use of these drugs is associated with positive or neucral effect on body weight and improvements in blood pressure, diabetic dyslipidemia, hepatic steazosis markets, and myocardial function. These effects have the potential to reduce the burden of cardiovascular disease, which is a major cause of mortality in patients with diabetes.

scholarly journals Oral DhHP-6 for the Treatment of Type 2 Diabetes Mellitus

2019 ◽  
Vol 20 (6) ◽  
pp. 1517 ◽  
Author(s):  
Kai Wang ◽  
Yu Su ◽  
Yuting Liang ◽  
Yanhui Song ◽  
Liping Wang
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Blood Glucose ◽  
Enzymatic Activity ◽  
Glucose Levels ◽  
Blood Glucose Levels

Type 2 diabetes mellitus (T2DM) is associated with pancreatic β-cell dysfunction which can be induced by oxidative stress. Deuterohemin-βAla-His-Thr-Val-Glu-Lys (DhHP-6) is a microperoxidase mimetic that can scavenge reactive oxygen species (ROS) in vivo. In our previous studies, we demonstrated an increased stability of linear peptides upon their covalent attachment to porphyrins. In this study, we assessed the utility of DhHP-6 as an oral anti-diabetic drug in vitro and in vivo. DhHP-6 showed high resistance to proteolytic degradation in vitro and in vivo. The degraded DhHP-6 product in gastrointestinal (GI) fluid retained the enzymatic activity of DhHP-6, but displayed a higher permeability coefficient. DhHP-6 protected against the cell damage induced by H2O2 and promoted insulin secretion in INS-1 cells. In the T2DM model, DhHP-6 reduced blood glucose levels and facilitated the recovery of blood lipid disorders. DhHP-6 also mitigated both insulin resistance and glucose tolerance. Most importantly, DhHP-6 promoted the recovery of damaged pancreas islets. These findings suggest that DhHP-6 in physiological environments has high stability against enzymatic degradation and maintains enzymatic activity. As DhHP-6 lowered the fasting blood glucose levels of T2DM mice, it thus represents a promising candidate for oral administration and clinical therapy.

scholarly journals Effect of Probiotics on the Glucose Levels of Pregnant Women: A Meta-Analysis of Randomized Controlled Trials

Medicina ◽  
2018 ◽  
Vol 54 (5) ◽  
pp. 77 ◽  
Author(s):  
Tzu-Rong Peng ◽  
Ta-Wei Wu ◽  
You-Chen Chao
Keyword(s):  
Blood Glucose ◽  
Randomized Controlled Trials ◽  
Pregnant Women ◽  
Cell Function ◽  
Fasting Blood Glucose ◽  
Controlled Trials ◽  
Model Assessment ◽  
Glucose Levels ◽  
Randomized Controlled ◽  
Blood Glucose Levels

Background: Gestational diabetes mellitus (GDM) is a condition, in which women develop high blood sugar levels during pregnancy without having diabetes. Evidence on the effects of probiotics on the blood glucose levels of women with GDM is inconsistent. Objective: The present study aimed to investigate the effects of probiotics on the blood glucose levels of pregnant women. Methods: Online databases, such as PubMed, Cochrane, and Excerpta Medica Database (EMBASE) were searched for randomized controlled trials (RCTs) published before July 2018. Trials had to meet the inclusion criteria of our study. Methodological quality and risk bias were independently assessed by two reviewers. Data were pooled using a random effects model and were expressed as the mean difference (MD) and 95% confidence interval (CI). Heterogeneity was evaluated and quantified as I2. Results: In total, 12 RCTs were included in this study. Studies have shown that the use of probiotics significantly reduced the fasting blood glucose (FBG) level (MD: −0.10 mmol/L; 95% CI: −0.19, −0.02), insulin concentration (MD: −2.24 μIU/mL; 95% CI: −3.69, −0.79), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) score (MD: −0.47; 95% CI: −0.74, −0.21), and Homeostasis model of assessment-estimated β cell function (HOMA-B) score (MD: −20.23; 95% CI: −31.98, −8.49) of pregnant women. In a subgroup analysis, whether the blood glucose-lowering effect of probiotics influenced the diagnosis of pregnant women with GDM was assessed. The results showed that probiotics had significantly reduced the fasting blood glucose (FBG) level (MD: −0.10 mmol/L; 95% CI: −0.17, −0.04) and HOMA-IR score (MD: −0.37; 95% CI: −0.72, −0.02) of pregnant women who were not diagnosed with GDM. Conclusion: Probiotics reduce the blood glucose level of pregnant women, especially without GDM diagnosis. However, further research using RCTs must be conducted to validate the results of the present study.

scholarly journals Dissecting the Brain/Islet Axis in Metabesity

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 350 ◽  
Author(s):  
Esther Fuente-Martín ◽  
Jose M. Mellado-Gil ◽  
Nadia Cobo-Vuilleumier ◽  
Alejandro Martín-Montalvo ◽  
Silvana Y. Romero-Zerbo ◽  
...  
Keyword(s):  
Common Factor ◽  
Critical Role ◽  
Cell Mass ◽  
Cell Types ◽  
Β Cell ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
High Prevalence ◽  
The Central Nervous System ◽  
Metabolic Dysfunctions

The high prevalence of type 2 diabetes mellitus (T2DM), together with the fact that current treatments are only palliative and do not avoid major secondary complications, reveals the need for novel approaches to treat the cause of this disease. Efforts are currently underway to identify therapeutic targets implicated in either the regeneration or re-differentiation of a functional pancreatic islet β-cell mass to restore insulin levels and normoglycemia. However, T2DM is not only caused by failures in β-cells but also by dysfunctions in the central nervous system (CNS), especially in the hypothalamus and brainstem. Herein, we review the physiological contribution of hypothalamic neuronal and glial populations, particularly astrocytes, in the control of the systemic response that regulates blood glucose levels. The glucosensing capacity of hypothalamic astrocytes, together with their regulation by metabolic hormones, highlights the relevance of these cells in the control of glucose homeostasis. Moreover, the critical role of astrocytes in the response to inflammation, a process associated with obesity and T2DM, further emphasizes the importance of these cells as novel targets to stimulate the CNS in response to metabesity (over-nutrition-derived metabolic dysfunctions). We suggest that novel T2DM therapies should aim at stimulating the CNS astrocytic response, as well as recovering the functional pancreatic β-cell mass. Whether or not a common factor expressed in both cell types can be feasibly targeted is also discussed.

scholarly journals Glycemic Variability in Diabetes Increases the Severity of Influenza

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Rebecca J. Marshall ◽  
Pornthida Armart ◽  
Katina D. Hulme ◽  
Keng Yih Chew ◽  
Alexandra C. Brown ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glycemic Variability ◽  
Endothelial Barrier ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Severe Influenza ◽  
Increased Risk ◽  
History Of

ABSTRACT People with diabetes are two times more likely to die from influenza than people with no underlying medical condition. The mechanisms underlying this susceptibility are poorly understood. In healthy individuals, small and short-lived postprandial peaks in blood glucose levels occur. In diabetes mellitus, these fluctuations become greater and more frequent. This glycemic variability is associated with oxidative stress and hyperinflammation. However, the contribution of glycemic variability to the pathogenesis of influenza A virus (IAV) has not been explored. Here, we used an in vitro model of the pulmonary epithelial-endothelial barrier and novel murine models to investigate the role of glycemic variability in influenza severity. In vitro, a history of glycemic variability significantly increased influenza-driven cell death and destruction of the epithelial-endothelial barrier. In vivo, influenza virus-infected mice with a history of glycemic variability lost significantly more body weight than mice with constant blood glucose levels. This increased disease severity was associated with markers of oxidative stress and hyperinflammation both in vitro and in vivo. Together, these results provide the first indication that glycemic variability may help drive the increased risk of severe influenza in people with diabetes mellitus. IMPORTANCE Every winter, people with diabetes are at increased risk of severe influenza. At present, the mechanisms that cause this increased susceptibility are unclear. Here, we show that the fluctuations in blood glucose levels common in people with diabetes are associated with severe influenza. These data suggest that glycemic stability could become a greater clinical priority for patients with diabetes during outbreaks of influenza.

scholarly journals Role of adrenoceptors in vitro and in vivo in the effects of lithium on blood glucose levels and insulin secretion in the rat

1990 ◽  
Vol 100 (2) ◽  
pp. 283-288 ◽  
Author(s):  
T. Fontela ◽  
O. García Hermida ◽  
J. Gómez-Acebo
Keyword(s):  
Insulin Secretion ◽  
Blood Glucose ◽  
Glucose Levels ◽  
Blood Glucose Levels

scholarly journals α-Cell Dysfunctions and Molecular Alterations in Male Insulinopenic Diabetic Mice Are Not Completely Corrected by Insulin

Endocrinology ◽  
2015 ◽  
Vol 157 (2) ◽  
pp. 536-547 ◽  
Author(s):  
Rodolphe Dusaulcy ◽  
Sandra Handgraaf ◽  
Mounia Heddad-Masson ◽  
Florian Visentin ◽  
Christian Vesin ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Insulin Treatment ◽  
Cell Function ◽  
Cell Mass ◽  
Glucagon Secretion ◽  
Diabetic Mice ◽  
Differentiation Markers ◽  
Molecular Alteration ◽  
Cell Dysfunction

Abstract Glucagon and α-cell dysfunction are critical in the development of hyperglycemia during diabetes both in humans and rodents. We hypothesized that α-cell dysfunction leading to dysregulated glucagon secretion in diabetes is due to both a lack of insulin and intrinsic defects. To characterize α-cell dysfunction in diabetes, we used glucagon-Venus transgenic male mice and induced insulinopenic hyperglycemia by streptozotocin administration leading to alterations of glucagon secretion. We investigated the in vivo impact of insulinopenic hyperglycemia on glucagon-producing cells using FACS-sorted α-cells from control and diabetic mice. We demonstrate that increased glucagonemia in diabetic mice is mainly due to increases of glucagon release and biosynthesis per cell compared with controls without changes in α-cell mass. We identified genes coding for proteins involved in glucagon biosynthesis and secretion, α-cell differentiation, and potential stress markers such as the glucagon, Arx, MafB, cMaf, Brain4, Foxa1, Foxa3, HNF4α, TCF7L2, Glut1, Sglt2, Cav2.1, Cav2.2, Nav1.7, Kir6.2/Sur1, Pten, IR, NeuroD1, GPR40, and Sumo1 genes, which were abnormally regulated in diabetic mice. Importantly, insulin treatment partially corrected α-cell function and expression of genes coding for proglucagon, or involved in glucagon secretion, glucose transport and insulin signaling but not those coding for cMAF, FOXA1, and α-cell differentiation markers as well as GPR40, NEUROD1, CAV2.1, and SUMO1. Our results indicate that insulinopenic diabetes induce marked α-cell dysfunction and molecular alteration, which are only partially corrected by in vivo insulin treatment.

scholarly journals Gastrin induces ductal cell dedifferentiation and β-cell neogenesis after 90% pancreatectomy

2014 ◽  
Vol 223 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Noèlia Téllez ◽  
Eduard Montanya
Keyword(s):  
Cell Mass ◽  
Β Cell ◽  
Neurogenin 3 ◽  
Glucose Levels ◽  
Ductal Cells ◽  
Blood Glucose Levels ◽  
Morphometric Analyses ◽  
Underlying Mechanisms ◽  
Mass Expansion

Induction of β-cell mass regeneration is a potentially curative treatment for diabetes. We have recently found that long-term gastrin treatment results in improved metabolic control and β-cell mass expansion in 95% pancreatectomised (Px) rats. In this study, we investigated the underlying mechanisms of gastrin-induced β-cell mass expansion after Px. After 90%-Px, rats were treated with gastrin (Px+G) or vehicle (Px+V), pancreatic remnants were harvested on days 1, 3, 5, 7, and 14 and used for gene expression, protein immunolocalisation and morphometric analyses. Gastrin- and vehicle-treated Px rats showed similar blood glucose levels throughout the study. Initially, after Px, focal areas of regeneration, showing mesenchymal cells surrounding ductal structures that expressed the cholecystokinin B receptor, were identified. These focal areas of regeneration were similar in size and cell composition in the Px+G and Px+V groups. However, in the Px+G group, the ductal structures showed lower levels of keratin 20 and β-catenin (indicative of duct dedifferentiation) and higher levels of expression of neurogenin 3 and NKX6-1 (indicative of endocrine progenitor phenotype), as compared with Px+V rats. In Px+G rats, β-cell mass and the number of scattered β-cells were significantly increased compared with Px+V rats, whereas β-cell replication and apoptosis were similar in the two groups. These results indicate that gastrin treatment-enhanced dedifferentiation and reprogramming of regenerative ductal cells in Px rats, increased β-cell neogenesis and fostered β-cell mass expansion.

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