scholarly journals SPARC is required for the maintenance of glucose homeostasis and insulin secretion in mice

2019 ◽  
Vol 133 (2) ◽  
pp. 351-365 ◽  
Author(s):  
Catalina Atorrasagasti ◽  
Agostina Onorato ◽  
María L. Gimeno ◽  
Luz Andreone ◽  
Mariana Garcia ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Glucose Transporter ◽  
Cell Types ◽  
High Fat ◽  
Metabolic Complications ◽  
Glucose Transporter 2 ◽  
Diabetes In Mice ◽  
Key Factor

Abstract Obesity, metabolic syndrome, and type 2 diabetes, three strongly interrelated diseases, are associated to increased morbidity and mortality worldwide. The pathogenesis of obesity-associated disorders is still under study. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein expressed in many cell types including adipocytes, parenchymal, and non-parenchymal hepatic cells and pancreatic cells. Studies have demonstrated that SPARC inhibits adipogenesis and promotes insulin resistance; in addition, circulating SPARC levels were positively correlated with body mass index in obese individuals. Therefore, SPARC is being proposed as a key factor in the pathogenesis of obesity-associated disorders. The aim of this study is to elucidate the role of SPARC in glucose homeostasis. We show here that SPARC null (SPARC−/−) mice displayed an abnormal insulin-regulated glucose metabolism. SPARC−/− mice presented an increased adipose tissue deposition and an impaired glucose homeostasis as animals aged. In addition, the absence of SPARC worsens high-fat diet-induced diabetes in mice. Interestingly, although SPARC−/− mice on high-fat diet were sensitive to insulin they showed an impaired insulin secretion capacity. Of note, the expression of glucose transporter 2 in islets of SPARC−/− mice was dramatically reduced. The present study provides the first evidence that deleted SPARC expression causes diabetes in mice. Thus, SPARC deficient mice constitute a valuable model for studies concerning obesity and its related metabolic complications, including diabetes.

scholarly journals The long non-coding RNA Pax6os1/PAX6-AS1 modulates pancreatic β-cell identity and function

2020 ◽  
Author(s):  
Livia Lopez-Noriega ◽  
Rebecca Callingham ◽  
Aida Martinez-Sánchez ◽  
Grazia Pizza ◽  
Nejc Haberman ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Pancreatic Islets ◽  
Glucose Homeostasis ◽  
High Glucose ◽  
High Fat Diet ◽  
High Fat ◽  
Β Cell ◽  
And Function

AbstractLong non-coding RNAs (lncRNAs) are emerging as crucial regulators of β-cell development and function. Consequently, the mis-expression of members of this group may contribute to the risk of type 2 diabetes (T2D). Here, we investigate roles for an antisense lncRNA expressed from the Pax6 locus (annotated as Pax6os1 in mice and PAX6-AS1 in humans) in β-cell function. The transcription factor Pax6 is required for the development of pancreatic islets and maintenance of a fully differentiated β-cell phenotype. Pax6os1/PAX6-AS1 expression was increased in pancreatic islets and β-cell lines at high glucose concentrations, in islets from mice fed a high fat diet, and in those from patients with type 2 diabetes. Silencing or deletion of Pax6os1/PAX6-AS1 in MIN6 cells and EndoC-βH1cells, respectively, upregulated β-cell signature genes, including insulin. Moreover, shRNA-mediated silencing of PAX6-AS1 in human islets not only increased insulin mRNA, but also enhanced glucose-stimulated insulin secretion and calcium dynamics. In contrast, inactivation of Pax6os1 in mice was largely without effect on glucose homeostasis, though female Pax6os1 null mice on high fat diet (HFD) showed a tendency towards enhanced glucose clearance. Together, our results suggest that increased expression of PAX6-AS1 at high glucose levels may contribute to β-cell dedifferentiation and failure in some forms of type 2 diabetes. Thus, targeting PAX6-AS1 may provide a promising strategy to enhance insulin secretion and improve glucose homeostasis in type 2 diabetes.

scholarly journals Inactivation of the dual Bmp/Wnt inhibitor Sostdc1 enhances pancreatic islet function

2012 ◽  
Vol 303 (6) ◽  
pp. E752-E761 ◽  
Author(s):  
Kathryn D. Henley ◽  
Kimberly A. Gooding ◽  
Aris N. Economides ◽  
Maureen Gannon
Keyword(s):  
Insulin Secretion ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Cell Function ◽  
Metabolic Stress ◽  
Islet Function ◽  
High Fat ◽  
Β Cell ◽  
Β Cell Function ◽  
Bmp Pathway

Current endeavors in the type 2 diabetes (T2D) field include gaining a better understanding of extracellular signaling pathways that regulate pancreatic islet function. Recent data suggest that both Bmp and Wnt pathways are operative in pancreatic islets and play a positive role in insulin secretion and glucose homeostasis. Our laboratory found the dual Bmp and Wnt antagonist Sostdc1 to be upregulated in a mouse model of islet dysmorphogenesis and nonimmune-mediated lean diabetes. Because Bmp signaling has been proposed to enhance β-cell function, we evaluated the role of Sostdc1 in adult islet function using animals in which Sostdc1 was globally deleted. While Sostdc1-null animals exhibited no pancreas development phenotype, a subset of mutants exhibited enhanced insulin secretion and improved glucose homeostasis compared with control animals after 12-wk exposure to high-fat diet. Loss of Sostdc1 in the setting of metabolic stress results in altered expression of Bmp-responsive genes in islets but did not affect expression of Wnt target genes, suggesting that Sostdc1 primarily regulates the Bmp pathway in the murine pancreas. Furthermore, our data indicate that removal of Sostdc1 enhances the downregulation of the closely related Bmp inhibitors Ctgf and Gremlin in islets after 8-wk exposure to high-fat diet. These data imply that Sostdc1 regulates expression of these inhibitors and provide a means by which Sostdc1-null animals show enhanced insulin secretion and glucose homeostasis. Our studies provide insights into Bmp pathway regulation in the endocrine pancreas and reveal new avenues for improving β-cell function under metabolic stress.

Comparative effects of telmisartan, sitagliptin and metformin alone or in combination on obesity, insulin resistance, and liver and pancreas remodelling in C57BL/6 mice fed on a very high-fat diet

2010 ◽  
Vol 119 (6) ◽  
pp. 239-250 ◽  
Author(s):  
Vanessa Souza-Mello ◽  
Bianca M. Gregório ◽  
Fernando S. Cardoso-de-Lemos ◽  
Laís de Carvalho ◽  
Márcia B. Aguila ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Hepatic Steatosis ◽  
High Fat Diet ◽  
Glucose Transporter ◽  
Oral Glucose ◽  
Free Access ◽  
High Fat ◽  
The Metabolic Syndrome ◽  
Glucose Transporter 2 ◽  
Drug Treatments

The aim of the present study was to evaluate the effects of monotherapies and combinations of drugs on insulin sensitivity, adipose tissue morphology, and pancreatic and hepatic remodelling in C57BL/6 mice fed on a very HF (high-fat) diet. Male C57BL/6 mice were fed on an HF (60% lipids) diet or SC (standard chow; 10% lipids) diet for 10 weeks, after which time the following drug treatments began: HF-T (HF diet treated with telmisartan; 5.2 mg·kg−1 of body weight·day−1), HF-S (HF diet treated with sitagliptin; 1.08 g·kg−1 of body weight·day−1), HF-M (HF diet treated with metformin; 310.0 mg·kg−1 of body weight·day−1), HF-TM (HF diet treated with telmisartan+metformin), HF-TS (HF diet treated with telmisartan+sitagliptin) and HF-SM (HF diet treated with sitagliptin+metformin). Treated groups also had free access to the HF diet, and treatments lasted for 6 weeks. Morphometry, stereological tools, immunostaining, ELISA, Western blot analysis and electron microscopy were used. The HF diet yielded an overweight phenotype, an increase in oral glucose intolerance, hyperinsulinaemia, hypertrophied islets and adipocytes, stage 2 steatosis (>33%), and reduced liver PPAR-α (peroxisome-proliferator-activated receptor-α) and GLUT-2 (glucose transporter-2) levels, concomitant with enhanced SREBP-1 (sterol-regulatory-element-binding protein-1) expression (P<0.0001). Conversely, all drug treatments resulted in significant weight loss, a reversal of insulin resistance, islet and adipocyte hypertrophy, and alleviated hepatic steatosis. Only the HF-T and HF-TS groups had body weights similar to the SC group at the end of the experiment, and the latter treatment reversed hepatic steatosis. Increased PPAR-α immunostaining in parallel with higher GLUT-2 and reduced SREBP-1 expression may explain the favourable hepatic outcomes. Restoration of adipocyte size was consistent with higher adiponectin levels and lower TNF-α (tumour necrosis factor-α) levels (P<0.0001) in the drug-treated groups. In conclusion, all of the drug treatments were effective in controlling the metabolic syndrome. The best results were achieved using telmisartan and sitagliptin as monotherapies or as a dual treatment, combining partial PPAR-γ agonism and PPAR-α activation in the liver with extended incretin action.

scholarly journals Lysophosphatidic acid impairs glucose homeostasis and inhibits insulin secretion in high-fat diet obese mice

Diabetologia ◽  
2013 ◽  
Vol 56 (6) ◽  
pp. 1394-1402 ◽  
Author(s):  
C. Rancoule ◽  
C. Attané ◽  
S. Grès ◽  
A. Fournel ◽  
R. Dusaulcy ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Homeostasis ◽  
Lysophosphatidic Acid ◽  
High Fat Diet ◽  
Obese Mice ◽  
High Fat

scholarly journals Effect of Ishophloroglucin A, A Component of Ishige okamurae, on Glucose Homeostasis in the Pancreas and Muscle of High Fat Diet-Fed Mice

Marine Drugs ◽  
2019 ◽  
Vol 17 (11) ◽  
pp. 608 ◽  
Author(s):  
Hye-Won Yang ◽  
Myeongjoo Son ◽  
Junwon Choi ◽  
Seyeon Oh ◽  
You-Jin Jeon ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Functional Food ◽  
Glucose Transporter ◽  
Fasting Glucose ◽  
High Fat ◽  
Β Cells ◽  
Glucose Levels ◽  
Ishige Okamurae ◽  
Prevention Of Diabetes

Ishophloroglucin A (IPA), a component of Ishige okamurae (IO), was previously evaluated to standardize the antidiabetic potency of IO. However, the potential of IPA as a functional food for diabetes prevention has not yet been evaluated. Here, we investigated if 1.35 mg/kg IPA, which is the equivalent content of IPA in 75 mg/kg IO, improved glucose homeostasis in high-fat diet (HFD)-induced diabetes after 12 weeks of treatment. IPA significantly ameliorated glucose intolerance, reducing fasting glucose levels as well as 2 h glucose levels in HFD mice. In addition, IPA exerted a protective effect on the pancreatic function in HFD mice via pancreatic β-cells and C-peptide. The level of glucose transporter 4 (GLUT4) in the muscles of HFD mice was stimulated by IPA intake. Our results suggested that IPA, which is a component of IO, can improve glucose homeostasis via GLUT4 in the muscles of HFD mice. IO may be used as a functional food for the prevention of diabetes.

scholarly journals Lactational Metformin Treatment in Mouse Dams Ameliorates Maternal High-Fat Diet-induced Metabolic Complications in Male Offspring

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Linh V Nguyen ◽  
Khanh V Doan ◽  
Keyword(s):  
Glucose Tolerance ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Maternal Obesity ◽  
Male Offspring ◽  
Lactation Period ◽  
Metformin Treatment ◽  
High Fat ◽  
Metabolic Complications

Maternal obesity/diabetes severely affects the offspring’s metabolism not only during the fetal and early life development but also later on in the childhood and adulthood stages. Recent evidence suggested that maternal metformin treatment during pregnancy and breastfeeding might provide long-term metabolic benefits on offspring’s glucose homeostasis. We employed a mouse model of maternal overnutrition induced by high fat diet (HFD) to investigate whether an early metformin treatment in mouse dams during lactation period attenuates the maternal HFD-induced metabolic complications in male offspring. The results showed that male offspring from metformin-exposed mothers during suckling period displayed lower body weight and decreased white fat contents. Furthermore, these male offspring had lower blood glucose levels, decreased hyperinsulinemia, enhanced glucose tolerance and insulin sensitivity. Moreover, we found that short-term metformin treatment during lactation period in mouse dams solely improved the glucose tolerance of male offspring exposed with high fat diet (HFD) during both in utero and early postnatal stages, which might primarily result from an increase in insulin secretion. However, this metformin treatment in mouse dams was enabled to abolish most of the metabolic complications of the male offspring exposed with HFD during lactation period. Together, these findings suggest that an early intervention in mouse dams by metformin treatment during lactation period may provide long-term metabolic benefits in regulation of male offspring’s glucose homeostasis.

scholarly journals Acute high-fat feeding leads to disruptions in glucose homeostasis and worsens stroke outcome

2017 ◽  
Vol 39 (6) ◽  
pp. 1026-1037 ◽  
Author(s):  
Michael J Haley ◽  
Siddharth Krishnan ◽  
David Burrows ◽  
Leon de Hoog ◽  
Jamie Thakrar ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Glucose Transporter ◽  
Artery Occlusion ◽  
Experimental Stroke ◽  
High Fat ◽  
Glut 1 ◽  
Fat Consumption ◽  
Fat Feeding ◽  
The Brain

Chronic consumption of diets high in fat leads to obesity and can negatively affect brain function. Rodents made obese by long-term maintenance on a high-fat diet have worse outcome after experimental stroke. High-fat consumption for only three days does not induce obesity but has rapid effects on the brain including memory impairment. However, the effect of brief periods of high-fat feeding or high-fat consumption in the absence of obesity on stroke is unknown. We therefore tested the effect of an acute period of high-fat feeding (three days) in C57B/6 mice on outcome after middle cerebral artery occlusion (MCAo). In contrast to a chronic high-fat diet (7.5 months), an acute high-fat diet had no effect on body weight, adipose tissue, lipid profile or inflammatory markers (in periphery and the brain). Three days of high-fat feeding impaired glucose tolerance, increased plasma glucose and insulin and brain expression of the glucose transporter GLUT-1. Ischaemic damage was increased (48%) in mice fed an acute high-fat diet, and was associated with a further reduction in GLUT-1 in the ischaemic hemisphere. These data demonstrate that only a brief period of high-fat consumption has a negative effect on glucose homeostasis and worsens outcome after ischaemic stroke.

scholarly journals Effects of Secretome from Fat Tissues on Ion Currents of Cardiomyocyte Modulated by Sodium-Glucose Transporter 2 Inhibitor

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3606
Author(s):  
Shih-Jie Jhuo ◽  
I-Hsin Liu ◽  
Wei-Chung Tsai ◽  
Te-Wu Chou ◽  
Yi-Hsiung Lin ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Glucose Transporter ◽  
Study Groups ◽  
Sglt2 Inhibitors ◽  
Delayed Rectifier ◽  
High Fat ◽  
Pericardial Fat ◽  
The Metabolic Syndrome ◽  
Glucose Transporter 2 ◽  
Significant Difference

Sodium-glucose transporter 2 (SGLT2) inhibitors were shown to decrease mortality from cardiovascular diseases in the EMPA-REG trial. However, the effects of empagliflozin (EMPA) for cardiac arrhythmia are not yet clarified. A total of 20 C57BL/6J mice were divided into four groups: (1) The control group were fed standard chow, (2) the metabolic syndrome (MS) group were fed a high-fat diet, (3) the empagliflozin (EMPA) group were fed a high-fat diet and empagliflozin 10 mg/kg daily, and (4) the glibenclamide (GLI) group were fed a high-fat diet and glibenclamide 0.6 mg/kg daily. All mice were sacrificed after 16 weeks of feeding. H9c2 cells were treated with adipocytokines from the pericardial and peripheral fat from the study groups. The delayed-rectifier potassium current (IK) and L-type calcium channel current (ICa,L) were measured by the whole-cell patch clamp techniques. Adipocytokines from the peripheral and pericardial fat tissues of mice with MS could decrease the IK and increase the ICa,L of cardiomyocytes. After treating adipocytokines from pericardial fat, the IK in the EMPA and GLI groups were significantly higher than that in the MS group. The IK of the EMPA group was also significantly higher than the GLI group. The ICa,L of the EMPA and GLI groups were significantly decreased overload compared with that of the MS group. However, there was no significant difference of IK and ICa,L among study groups after treating adipocytokines from peripheral fat. Adipocytokines from pericardial fat but not peripheral fat tissues after EMPA therapy attenuated the effects of IK decreasing and ICa,L increasing in the MS cardiomyocytes, which may contribute to anti-arrhythmic mechanisms of sodium-glucose transporter 2 (SGLT2) inhibitors.

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