scholarly journals CaMKIV limits metabolic damage through induction of hepatic autophagy by CREB in obese mice

2020 ◽  
Vol 244 (2) ◽  
pp. 353-367 ◽  
Author(s):  
Jiali Liu ◽  
Yue Li ◽  
Xiaoyan Zhou ◽  
Xi Zhang ◽  
Hao Meng ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Inflammatory Response ◽  
Mitochondrial Dysfunction ◽  
High Fat Diet ◽  
Insulin Action ◽  
Hepatic Insulin Resistance ◽  
Obese Mice ◽  
High Fat ◽  
Impaired Insulin

High-fat diet (HFD) not only induces insulin resistance in liver, but also causes autophagic imbalance and metabolic disorders, increases chronic inflammatory response and induces mitochondrial dysfunction. Calcium/calmodulin-dependent protein kinase IV (CaMKIV) has recently emerged as an important regulator of glucose metabolism and skeletal muscle insulin action. Its activation has been involved in the improvement of hepatic and adipose insulin action. But the underlying mechanism is not fully understood. In the present study, we aimed to address the direct effects of CaMKIV in vivo and to evaluate the potential interaction of impaired insulin sensitivity and autophagic disorders in hepatic insulin resistance. Our results indicated obese mice receiving CaMKIV showed decreased blood glucose and serum insulin and improved insulin sensitivity as well as increased glucose tolerance compared with vehicle injection. Meanwhile, defective hepatic autophagy activity, impaired insulin signaling, increased inflammatory response and mitochondrial dysfunction in liver tissues which are induced by high-fat diet were also effectively alleviated by injection of CaMKIV. Consistent with these results, the addition of CaMKIV to the culture medium of BNL cl.2 hepatocytes markedly restored palmitate-induced hepatic insulin resistance and autophagic imbalance. These effects were nullified by blockade of cyclic AMP response element-binding protein (CREB), indicating the causative role of CREB in action of CaMKIV. Our findings suggested that CaMKIV restores hepatic autophagic imbalance and improves impaired insulin sensitivity via phosphorylated CREB signaling pathway, which may offer novel opportunities for treatment of obesity and diabetes.

scholarly journals Selenoprotein W deficiency does not affect oxidative stress and insulin sensitivity in the skeletal muscle of high-fat diet-fed obese mice

2019 ◽  
Vol 317 (6) ◽  
pp. C1172-C1182 ◽  
Author(s):  
Min-Gyeong Shin ◽  
Hye-Na Cha ◽  
Soyoung Park ◽  
Yong-Woon Kim ◽  
Jong-Yeon Kim ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Control Diet ◽  
In Vivo Studies ◽  
Selenoprotein W ◽  
Obese Mice ◽  
High Fat

Selenoprotein W (SelW) is a selenium-containing protein with a redox motif found abundantly in the skeletal muscle of rodents. Previous in vitro studies suggest that SelW plays an antioxidant role; however, relatively few in vivo studies have addressed the antioxidant role of SelW. Since oxidative stress is a causative factor for the development of insulin resistance in obese subjects, we hypothesized that if SelW plays a role as an antioxidant, SelW deficiency could aggravate the oxidative stress and insulin resistance caused by a high-fat diet. SelW deficiency did not affect insulin sensitivity and H2O2 levels in the skeletal muscle of control diet-fed mice. SelW levels in the skeletal muscle were decreased by high-fat diet feeding for 12 wk. High-fat diet induced obesity and insulin resistance and increased the levels of H2O2 and oxidative stress makers, which were not affected by SelW deficiency. High-fat diet feeding increased the expression of antioxidant enzymes; however, SelW deficiency did not affect the expression levels of antioxidants. These results suggest that SelW does not play a protective role against oxidative stress and insulin resistance in the skeletal muscle of high-fat diet-fed obese mice.

scholarly journals Double-Stranded RNA-Activated Protein Kinase Is a Key Modulator of Insulin Sensitivity in Physiological Conditions and in Obesity in Mice

Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5261-5274 ◽  
Author(s):  
M. A. Carvalho-Filho ◽  
B. M. Carvalho ◽  
A. G. Oliveira ◽  
D. Guadagnini ◽  
M. Ueno ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Protein Phosphatase ◽  
High Fat Diet ◽  
Obese Mice ◽  
High Fat ◽  
Double Stranded Rna ◽  
Physiological Conditions ◽  
Phosphatase 2A

Abstract The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr−/− and Pkr+/+ mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr−/− mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase β. Pkr−/− mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase β phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.

scholarly journals Comparative effects of sex hormone deprivation on the brain of insulin-resistant rats

2019 ◽  
Vol 241 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Jirapas Sripetchwandee ◽  
Hiranya Pintana ◽  
Piangkwan Sa-nguanmoo ◽  
Chiraphat Boonnag ◽  
Wasana Pratchayasakul ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Cognitive Decline ◽  
Mitochondrial Dysfunction ◽  
Dendritic Spine ◽  
High Fat Diet ◽  
High Fat ◽  
Long Term Depression ◽  
Impaired Insulin

Obese-insulin resistance following chronic high-fat diet consumption led to cognitive decline through several mechanisms. Moreover, sex hormone deprivation, including estrogen and testosterone, could be a causative factor in inducing cognitive decline. However, comparative studies on the effects of hormone deprivation on the brain are still lacking. Adult Wistar rats from both genders were operated upon (sham operations or orchiectomies/ovariectomies) and given a normal diet or high-fat diet for 4, 8 and 12 weeks. Blood was collected to determine the metabolic parameters. At the end of the experiments, rats were decapitated and their brains were collected to determine brain mitochondrial function, brain oxidative stress, hippocampal plasticity, insulin-induced long-term depression, dendritic spine density and cognition. We found that male and female rats fed a high-fat diet developed obese-insulin resistance by week 8 and brain defects via elevated brain oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression, hippocampal dysplasticity, reduced dendritic spine density and cognitive decline by week 12. In normal diet-fed rats, estrogen deprivation, not testosterone deprivation, induced obese-insulin resistance, oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression, hippocampal dysplasticity and reduced dendritic spine density. In high-fat–diet-fed rats, estrogen deprivation, not testosterone deprivation, accelerated and aggravated obese-insulin resistance and brain defects at week 8. In conclusion, estrogen deprivation aggravates brain dysfunction more than testosterone deprivation through increased oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression and dendritic spine reduction. These findings may explain clinical reports which show more severe cognitive decline in aging females than males with obese-insulin resistance.

scholarly journals Effect of Thunbergia laurifolia water extracts on hepatic insulin resistance in high-fat diet-induced obese mice

2021 ◽  
Vol 11 (3) ◽  
pp. 97
Author(s):  
Jarinyaporn Naowaboot ◽  
Urarat Nanna ◽  
Linda Chularojmontri ◽  
Pholawat Tingpej ◽  
Patchareewan Pannangpetch
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Obese Mice ◽  
High Fat ◽  
Water Extracts ◽  
Thunbergia Laurifolia

DNA Repair Enzyme Ogg1 Regulates Hepatic Insulin Resistance in High-Fat Diet-Fed Obese Mice

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 235-LB
Author(s):  
LARYSA YUZEFOVYCH ◽  
MICHELE SCHULER ◽  
HYE LIM NOH ◽  
SUJIN SUK ◽  
JASON K. KIM ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Dna Repair ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Obese Mice ◽  
High Fat ◽  
Repair Enzyme

scholarly journals Lemon Balm Extract ALS-L1023 Regulates Obesity and Improves Insulin Sensitivity via Activation of Hepatic PPARα in High-Fat Diet-Fed Obese C57BL/6J Mice

2020 ◽  
Vol 21 (12) ◽  
pp. 4256
Author(s):  
Dongju Lee ◽  
Yujin Shin ◽  
Jong Seong Roh ◽  
Jiwon Ahn ◽  
Sunhyo Jeoong ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Lipid Accumulation ◽  
High Fat Diet ◽  
Obese Mice ◽  
High Fat ◽  
Lemon Balm ◽  
Hepatic Lipid ◽  
Hepatic Lipid Accumulation

Our previous studies demonstrated that peroxisome proliferator-activated receptor α (PPARα) activation reduces weight gain and improves insulin sensitivity in obese mice. Since excess lipid accumulation in non-adipose tissues is suggested to be responsible for the development of insulin resistance, this study was undertaken to examine whether the lemon balm extract ALS-L1023 regulates hepatic lipid accumulation, obesity, and insulin resistance and to determine whether its mechanism of action involves PPARα. Administration of ALS-L1023 to high-fat-diet-induced obese mice caused reductions in body weight gain, visceral fat mass, and visceral adipocyte size without changes of food consumption profiles. ALS-L1023 improved hyperglycemia, hyperinsulinemia, glucose and insulin tolerance, and normalized insulin-positive β-cell area in obese mice. ALS-L1023 decreased hepatic lipid accumulation and concomitantly increased the expression of PPARα target genes responsible for fatty acid β-oxidation in livers. In accordance with the in vivo data, ALS-L1023 reduced lipid accumulation and stimulated PPARα reporter gene expression in HepG2 cells. These effects of ALS-L1023 were comparable to those of the PPARα ligand fenofibrate, while the PPARα antagonist GW6471 inhibited the actions of ALS-L1023 on lipid accumulation and PPARα luciferase activity in HepG2 cells. Higher phosphorylated protein kinase B (pAkt)/Akt ratios and lower expression of gluconeogenesis genes were observed in the livers of ALS-L1023-treated mice. These results indicate that ALS-L1023 may inhibit obesity and improve insulin sensitivity in part through inhibition of hepatic lipid accumulation via hepatic PPARα activation.

Morin attenuates hepatic insulin resistance in high-fat-diet-induced obese mice

2016 ◽  
Vol 72 (2) ◽  
pp. 269-280 ◽  
Author(s):  
Jarinyaporn Naowaboot ◽  
Supaporn Wannasiri ◽  
Patchareewan Pannangpetch
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Obese Mice ◽  
High Fat

scholarly journals Osteocalcin Reverses Endoplasmic Reticulum Stress and Improves Impaired Insulin Sensitivity Secondary to Diet-Induced Obesity Through Nuclear Factor-κB Signaling Pathway

Endocrinology ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 1055-1068 ◽  
Author(s):  
Bo Zhou ◽  
Huixia Li ◽  
Lin Xu ◽  
Weijin Zang ◽  
Shufang Wu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Endoplasmic Reticulum ◽  
Insulin Sensitivity ◽  
Er Stress ◽  
High Fat Diet ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Phosphatidylinositol 3 Kinase ◽  
High Fat ◽  
Impaired Insulin

Abstract Osteocalcin, a synthetic osteoblast-specific protein, has recently emerged as an important regulator of energy metabolism, but the underlying mechanisms are not fully understood. In the present study, mice fed a high-fat diet and receiving osteocalcin showed reduced body weight gain, less fat pad gain, and improved insulin sensitivity as well as increased energy expenditure compared with mice fed a high-fat diet and receiving vehicle. Meanwhile, increased endoplasmic reticulum (ER) stress, defective insulin signaling, and mitochondrial dysfunction induced by obesity were also effectively alleviated by treatment with osteocalcin. Consistent with these findings, the addition of osteocalcin to the culture medium of 3T3-L1 adipocytes, Fao liver cells, and L6 muscle cells markedly reduced ER stress and restored insulin sensitivity. These effects were nullified by blockade of nuclear factor–κB (NF-κB) or phosphatidylinositol 3-kinase but not by U0126, a mitogen-activated protein kinase inhibitor, indicating the causative role of phosphatidylinositol 3-kinase/NF-κB in action of osteocalcin. In addition, the reversal effects of osteocalcin in cells deficient in X-box–binding protein-1, a transcription factor that modulates ER stress response, further confirmed its protective role against ER stress and insulin resistance. Our findings suggest that osteocalcin attenuates ER stress and rescues impaired insulin sensitivity in insulin resistance via the NF-κB signaling pathway, which may offer novel opportunities for treatment of obesity and diabetes.

Adipose tissue inflammation contributes to short-term high-fat diet-induced hepatic insulin resistance

2013 ◽  
Vol 305 (3) ◽  
pp. E388-E395 ◽  
Author(s):  
Michael S. F. Wiedemann ◽  
Stephan Wueest ◽  
Flurin Item ◽  
Eugen J. Schoenle ◽  
Daniel Konrad
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Adipose Tissue Inflammation ◽  
High Fat ◽  
Hepatic Insulin Sensitivity ◽  
Tissue Inflammation

High-fat feeding for 3–4 days impairs glucose tolerance and hepatic insulin sensitivity. However, it remains unclear whether the evolving hepatic insulin resistance is due to acute lipid overload or the result of induced adipose tissue inflammation and consequent dysfunctional adipose tissue-liver cross-talk. In the present study, feeding C57Bl6/J mice a fat-enriched diet [high-fat diet (HFD)] for 4 days induced glucose intolerance, hepatic insulin resistance (as assessed by hyperinsulinemic euglycemic clamp studies), and hepatic steatosis as well as adipose tissue inflammation (i.e., TNFα expression) compared with standard chow-fed mice. Adipocyte-specific depletion of the antiapoptotic/anti-inflammatory factor Fas (CD95) attenuated adipose tissue inflammation and improved glucose tolerance as well as hepatic insulin sensitivity without altering the level of hepatic steatosis induced by HFD. In summary, our results identify adipose tissue inflammation and resulting dysfunctional adipose tissue-liver cross-talk as an early event in the development of HFD-induced hepatic insulin resistance.

Sign in / Sign up

Export Citation Format

Share Document