scholarly journals Sustained ER stress promotes hyperglycemia by increasing glucagon action through the deubiquitinating enzyme USP14

2019 ◽  
Vol 116 (43) ◽  
pp. 21732-21738 ◽  
Author(s):  
Bin Liu ◽  
Zhijian Zhang ◽  
Yanyun Hu ◽  
Yan Lu ◽  
Duanzhuo Li ◽  
...  
Keyword(s):  
Er Stress ◽  
Metabolic Diseases ◽  
Low Grade ◽  
Deubiquitinating Enzyme ◽  
Obese Mice ◽  
Hepatic Gluconeogenesis ◽  
Regulatory Pathways ◽  
Underlying Mechanisms ◽  
The Stability ◽  
Glucose Output

Endoplasmic reticulum (ER) stress plays an important role in metabolic diseases like obesity and type 2 diabetes mellitus (T2DM), although the underlying mechanisms and regulatory pathways remain to be elucidated. Here, we induced chronic low-grade ER stress in lean mice to levels similar to those in high-fat diet (HFD)–fed obese mice and found that it promoted hyperglycemia due to enhanced hepatic gluconeogenesis. Mechanistically, sustained ER stress up-regulated the deubiquitinating enzyme ubiquitin-specific peptidase 14 (USP14), which increased the stability and levels of 3′,5′-cyclic monophosphate–responsive element binding (CREB) protein (CBP) to enhance glucagon action and hepatic gluconeogenesis. Exogenous overexpression of USP14 in the liver significantly increased hepatic glucose output. Consistent with this, liver-specific knockdown of USP14 abrogated the effects of ER stress on glucose metabolism, and also improved hyperglycemia and glucose intolerance in obese mice. In conclusion, our findings show a mechanism underlying ER stress-induced disruption of glucose homeostasis, and present USP14 as a potential therapeutic target against T2DM.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Gut microbiota in patients with type 2 diabetes mellitus

2015 ◽  
Vol 172 (4) ◽  
pp. R167-R177 ◽  
Author(s):  
Kristine H Allin ◽  
Trine Nielsen ◽  
Oluf Pedersen
Keyword(s):  
Type 2 Diabetes ◽  
Gut Microbiota ◽  
Metabolic Diseases ◽  
Short Chain Fatty Acids ◽  
Intestinal Content ◽  
Low Grade ◽  
Bacterial Fermentation ◽  
Underlying Mechanisms

Perturbations of the composition and function of the gut microbiota have been associated with metabolic disorders including obesity, insulin resistance and type 2 diabetes. Studies on mice have demonstrated several underlying mechanisms including host signalling through bacterial lipopolysaccharides derived from the outer membranes of Gram-negative bacteria, bacterial fermentation of dietary fibres to short-chain fatty acids and bacterial modulation of bile acids. On top of this, an increased permeability of the intestinal epithelium may lead to increased absorption of macromolecules from the intestinal content resulting in systemic immune responses, low-grade inflammation and altered signalling pathways influencing lipid and glucose metabolism. While mechanistic studies on mice collectively support a causal role of the gut microbiota in metabolic diseases, the majority of studies in humans are correlative of nature and thus hinder causal inferences. Importantly, several factors known to influence the risk of type 2 diabetes, e.g. diet and age, have also been linked to alterations in the gut microbiota complicating the interpretation of correlative studies. However, based upon the available evidence, it is hypothesised that the gut microbiota may mediate or modulate the influence of lifestyle factors triggering development of type 2 diabetes. Thus, the aim of this review is to critically discuss the potential role of the gut microbiota in the pathophysiology and pathogenesis of type 2 diabetes.

scholarly journals Control of Hepatic Gluconeogenesis by the Promyelocytic Leukemia Zinc Finger Protein

2014 ◽  
Vol 28 (12) ◽  
pp. 1987-1998 ◽  
Author(s):  
Siyu Chen ◽  
Jinchun Qian ◽  
Xiaoli Shi ◽  
Tingting Gao ◽  
Tingming Liang ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Metabolic Diseases ◽  
Zinc Finger Protein ◽  
Promyelocytic Leukemia ◽  
Peroxisome Proliferator ◽  
Hepatic Gluconeogenesis ◽  
Promyelocytic Leukemia Zinc Finger ◽  
Peroxisome Proliferator Activated Receptor ◽  
Hepatic Glucose ◽  
Glucose Output

The promyelocytic leukemia zinc finger (PLZF) protein is involved in major biological processes including energy metabolism, although its role remains unknown. In this study, we demonstrated that hepatic PLZF expression was induced in fasted or diabetic mice. PLZF promoted gluconeogenic gene expression and hepatic glucose output, leading to hyperglycemia. In contrast, hepatic PLZF knockdown improved glucose homeostasis in db/db mice. Mechanistically, peroxisome proliferator-activated receptor γ coactivator 1α and the glucocorticoid receptor synergistically activated PLZF expression. We conclude that PLZF is a critical regulator of hepatic gluconeogenesis. PLZF manipulation may benefit the treatment of metabolic diseases associated with gluconeogenesis.

CHOP is Dispensable for Exercise-Induced Increases in GDF15

2021 ◽  
Author(s):  
Logan K. Townsend ◽  
Kyle D. Medak ◽  
Alyssa J. Weber ◽  
Hana Dibe ◽  
Hesham Shamshoum ◽  
...  
Keyword(s):  
Er Stress ◽  
Acute Exercise ◽  
Stress Protein ◽  
Whole Body ◽  
Obese Mice ◽  
Stress Markers ◽  
Wide Range ◽  
Underlying Mechanisms ◽  
Exercise Induced ◽  
Deficient Mice

Growth differentiating factor-15 (GDF15) is expressed, and secreted, from a wide range of tissues and serves as a marker of cellular stress. A key transcriptional regulator of this hormone is the endoplasmic reticulum stress protein, CHOP (C/EBP Homologous Protein). Exercise increases GDF15 levels but the underlying mechanisms of this are not known. To test whether CHOP regulates GDF15 during exercise we used various models of altered ER stress. We examined the effects of acute exercise on circulating GDF15 and GDF15 mRNA expression in liver, triceps skeletal muscle, and epididymal white adipose tissue and examined the GDF15 response to acute exercise in lean and high-fat diet-induced obese mice, sedentary and exercise trained mice, and CHOP deficient mice. We found that obesity augments exercise-induced circulating GDF15 although ER stress markers were similar in lean and obese mice. Exercise-induced GDF15 was increased in trained and sedentary mice that ran at the same relative exercise intensity, despite trained mice being protected against increased markers of ER stress. Finally, exercise-induced increases in GDF15 at the tissue and whole-body level were intact in CHOP deficient mice. Together, these results provide evidence that exercise-induced GDF15 expression and secretion occurs independent of ER stress/CHOP.

scholarly journals Association of Adipose Tissue and Adipokines with Development of Obesity-Induced Liver Cancer

2021 ◽  
Vol 22 (4) ◽  
pp. 2163
Author(s):  
Yetirajam Rajesh ◽  
Devanand Sarkar
Keyword(s):  
Adipose Tissue ◽  
Cancer Progression ◽  
Metabolic Diseases ◽  
Low Grade ◽  
Metabolic Complications ◽  
Endocrine Organ ◽  
Nonalcoholic Fatty Liver ◽  
Underlying Mechanisms ◽  
Low Grade Inflammation ◽  
Excessive Accumulation

Obesity is rapidly dispersing all around the world and is closely associated with a high risk of metabolic diseases such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease (NAFLD), leading to carcinogenesis, especially hepatocellular carcinoma (HCC). It results from an imbalance between food intake and energy expenditure, leading to an excessive accumulation of adipose tissue (AT). Adipocytes play a substantial role in the tumor microenvironment through the secretion of several adipokines, affecting cancer progression, metastasis, and chemoresistance via diverse signaling pathways. AT is considered an endocrine organ owing to its ability to secrete adipokines, such as leptin, adiponectin, resistin, and a plethora of inflammatory cytokines, which modulate insulin sensitivity and trigger chronic low-grade inflammation in different organs. Even though the precise mechanisms are still unfolding, it is now established that the dysregulated secretion of adipokines by AT contributes to the development of obesity-related metabolic disorders. This review focuses on several obesity-associated adipokines and their impact on obesity-related metabolic diseases, subsequent metabolic complications, and progression to HCC, as well as their role as potential therapeutic targets. The field is rapidly developing, and further research is still required to fully understand the underlying mechanisms for the metabolic actions of adipokines and their role in obesity-associated HCC.

scholarly journals Therapeutic Roles of Heme Oxygenase-1 in Metabolic Diseases: Curcumin and Resveratrol Analogues as Possible Inducers of Heme Oxygenase-1

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yong Son ◽  
Ju Hwan Lee ◽  
Hun-Taeg Chung ◽  
Hyun-Ock Pae
Keyword(s):  
Oxidative Stress ◽  
Er Stress ◽  
Heme Oxygenase ◽  
Stress Responses ◽  
Metabolic Diseases ◽  
Heme Oxygenase 1 ◽  
Low Grade ◽  
Inflammatory Stress ◽  
Resveratrol Analogues ◽  
Stress Oxidative

Metabolic diseases, such as insulin resistance, type II diabetes, and obesity, are associated with a low-grade chronic inflammation (inflammatory stress), oxidative stress, and endoplasmic reticulum (ER) stress. Because the integration of these stresses is critical to the pathogenesis of metabolic diseases, agents and cellular molecules that can modulate these stress responses are emerging as potential targets for intervention and treatment of metabolic diseases. It has been recognized that heme oxygenase-1 (HO-1) plays an important role in cellular protection. Because HO-1 can reduce inflammatory stress, oxidative stress, and ER stress, in part by exerting antioxidant, anti-inflammatory, and antiapoptotic effects, HO-1 has been suggested to play important roles in pathogenesis of metabolic diseases. In the present review, we will explore our current understanding of the protective mechanisms of HO-1 in metabolic diseases and present some emerging therapeutic options for HO-1 expression in treating metabolic diseases, together with the therapeutic potential of curcumin and resveratrol analogues that have their ability to induce HO-1 expression.

scholarly journals Akkermansia muciniphila improves metabolic profiles by reducing inflammation in chow diet-fed mice

2017 ◽  
Vol 58 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Shaoqian Zhao ◽  
Wen Liu ◽  
Jiqiu Wang ◽  
Juan Shi ◽  
Yingkai Sun ◽  
...  
Keyword(s):  
Body Weight ◽  
Glucose Tolerance ◽  
Metabolic Diseases ◽  
Body Weight Gain ◽  
Inflammatory Factors ◽  
Chow Diet ◽  
Low Grade ◽  
Akkermansia Muciniphila ◽  
Inflammatory Status ◽  
Underlying Mechanisms

Abnormal shifts in the composition of gut microbiota contribute to the pathogenesis of metabolic diseases, including obesity and type 2 diabetes (T2DM). The crosstalk between gut microbes and the host affects the inflammatory status and glucose tolerance of the individuals, but the underlying mechanisms have not been elucidated completely. In this study, we treated the lean chow diet-fed mice with Akkermansia muciniphila, which is thought to be inversely correlated with inflammation status and body weight in rodents and humans, and we found that A. muciniphila supplementation by daily gavage for five weeks significantly alleviated body weight gain and reduced fat mass. Glucose tolerance and insulin sensitivity were also improved by A. muciniphila supplementation compared with the vehicle. Furthermore, A. muciniphila supplementation reduced gene expression related to fatty acid synthesis and transport in liver and muscle; meanwhile, endoplasmic reticulum (ER) stress in liver and muscle was also alleviated by A. muciniphila. More importantly, A. muciniphila supplementation reduced chronic low-grade inflammation, as reflected by decreased plasma levels of lipopolysaccharide (LPS)-binding protein (LBP) and leptin, as well as inactivated LPS/LBP downstream signaling (e.g. decreased phospho-JNK and increased IKBA expression) in liver and muscle. Moreover, metabolomics profiling in plasma also revealed an increase in anti-inflammatory factors such as α-tocopherol, β-sitosterol and a decrease of representative amino acids. In summary, our study demonstrated that A. muciniphila supplementation relieved metabolic inflammation, providing underlying mechanisms for the interaction of A. muciniphila and host health, pointing to possibilities for metabolic benefits using specific probiotics supplementation in metabolic healthy individuals.

The Inflammation Network in the Pathogenesis of Erectile Dysfunction: Attractive Potential Therapeutic Targets

2020 ◽  
Vol 26 (32) ◽  
pp. 3955-3972
Author(s):  
Ecem Kaya-Sezginer ◽  
Serap Gur
Keyword(s):  
Erectile Dysfunction ◽  
Endothelial Dysfunction ◽  
Metabolic Diseases ◽  
Inflammatory Marker ◽  
Attractive Potential ◽  
Common Denominator ◽  
Low Grade ◽  
Antiinflammatory Drugs ◽  
Male Population ◽  
Low Grade Inflammation

Background: Erectile dysfunction (ED) is an evolving health problem in the aging male population. Chronic low-grade inflammation is a critical component of ED pathogenesis and a probable intermediate stage of endothelial dysfunction, especially in metabolic diseases, with the inclusion of obesity, metabolic syndrome, and diabetes. Objective: This review will present an overview of preclinical and clinical data regarding common inflammatory mechanisms involved in the pathogenesis of ED associated with metabolic diseases and the effect of antiinflammatory drugs on ED. Methods: A literature search of existing pre-clinical and clinical studies was performed on databases [Pubmed (MEDLINE), Scopus, and Embase] from January 2000 to October 2019. Results: Low-grade inflammation is a possible pathological role in endothelial dysfunction as a consequence of ED and other related metabolic diseases. Increased inflammation and endothelial/prothrombotic markers can be associated with the presence and degree of ED. Pharmacological therapy and modification of lifestyle and risk factors may have a significant role in the recovery of erectile response through reduction of inflammatory marker levels. Conclusion: Inflammation is the least common denominator in the pathology of ED and metabolic disorders. The inflammatory process of ED includes a shift in the complex interactions of cytokines, chemokines, and adhesion molecules. These data have established that anti-inflammatory agents could be used as a therapeutic opportunity in the prevention and treatment of ED. Further research on inflammation-related mechanisms underlying ED and the effect of therapeutic strategies aimed at reducing inflammation is required for a better understanding of the pathogenesis and successful management of ED.

Periodontal Pathogens and Neuropsychiatric Health

2020 ◽  
Vol 20 (15) ◽  
pp. 1353-1397 ◽  
Author(s):  
Abhishek Wadhawan ◽  
Mark A. Reynolds ◽  
Hina Makkar ◽  
Alison J. Scott ◽  
Eileen Potocki ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Low Grade ◽  
Periodontal Pathogens ◽  
Synergistic Interactions ◽  
Brain Vasculature ◽  
Micro Rnas ◽  
Clinical Conditions ◽  
Low Grade Inflammation ◽  
Neuropsychiatric Illness

Increasing evidence incriminates low-grade inflammation in cardiovascular, metabolic diseases, and neuropsychiatric clinical conditions, all important causes of morbidity and mortality. One of the upstream and modifiable precipitants and perpetrators of inflammation is chronic periodontitis, a polymicrobial infection with Porphyromonas gingivalis (P. gingivalis) playing a central role in the disease pathogenesis. We review the association between P. gingivalis and cardiovascular, metabolic, and neuropsychiatric illness, and the molecular mechanisms potentially implicated in immune upregulation as well as downregulation induced by the pathogen. In addition to inflammation, translocation of the pathogens to the coronary and peripheral arteries, including brain vasculature, and gut and liver vasculature has important pathophysiological consequences. Distant effects via translocation rely on virulence factors of P. gingivalis such as gingipains, on its synergistic interactions with other pathogens, and on its capability to manipulate the immune system via several mechanisms, including its capacity to induce production of immune-downregulating micro-RNAs. Possible targets for intervention and drug development to manage distal consequences of infection with P. gingivalis are also reviewed.

scholarly journals Homocysteine Induces Apoptosis of Human Umbilical Vein Endothelial Cells via Mitochondrial Dysfunction and Endoplasmic Reticulum Stress

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Zhimin Zhang ◽  
Congying Wei ◽  
Yanfen Zhou ◽  
Tao Yan ◽  
Zhengqiang Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Umbilical Vein ◽  
Dependent Manner ◽  
Human Umbilical Vein ◽  
Homologous Protein ◽  
Intracellular Ros ◽  
Underlying Mechanisms ◽  
Umbilical Vein Endothelial Cells

Homocysteine- (Hcy-) induced endothelial cell apoptosis has been suggested as a cause of Hcy-dependent vascular injury, while the proposed molecular pathways underlying this process are unclear. In this study, we investigated the adverse effects of Hcy on human umbilical vein endothelial cells (HUVEC) and the underlying mechanisms. Our results demonstrated that moderate-dose Hcy treatment induced HUVEC apoptosis in a time-dependent manner. Furthermore, prolonged Hcy treatment increased the expression of NOX4 and the production of intracellular ROS but decreased the ratio of Bcl-2/Bax and mitochondrial membrane potential (MMP), resulting in the leakage of cytochrome c and activation of caspase-3. Prolonged Hcy treatment also upregulated glucose-regulated protein 78 (GRP78), activated protein kinase RNA-like ER kinase (PERK), and induced the expression of C/EBP homologous protein (CHOP) and the phosphorylation of NF-κb. The inhibition of NOX4 decreased the production of ROS and alleviated the Hcy-induced HUVEC apoptosis and ER stress. Blocking the PERK pathway partly alleviated Hcy-induced HUVEC apoptosis and the activation of NF-κb. Taken together, our results suggest that Hcy-induced mitochondrial dysfunction crucially modulated apoptosis and contributed to the activation of ER stress in HUVEC. The excessive activation of the PERK pathway partly contributed to Hcy-induced HUVEC apoptosis and the phosphorylation of NF-κb.

scholarly journals Impact of Dietary Flavanols on Microbiota, Immunity and Inflammation in Metabolic Diseases

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 850
Author(s):  
María Ángeles Martín ◽  
Sonia Ramos
Keyword(s):  
Immune System ◽  
Fruits And Vegetables ◽  
Metabolic Diseases ◽  
Nuclear Factor Κb ◽  
Low Grade ◽  
Beneficial Effects ◽  
Health And Disease ◽  
Immunological Reactions ◽  
And Function ◽  
Positive Properties

Flavanols are natural occurring polyphenols abundant in fruits and vegetables to which have been attributed to beneficial effects on health, and also against metabolic diseases, such as diabetes, obesity and metabolic syndrome. These positive properties have been associated to the modulation of different molecular pathways, and importantly, to the regulation of immunological reactions (pro-inflammatory cytokines, chemokines, adhesion molecules, nuclear factor-κB [NF-κB], inducible enzymes), and the activity of cells of the immune system. In addition, flavanols can modulate the composition and function of gut microbiome in a prebiotic-like manner, resulting in the positive regulation of metabolic pathways and immune responses, and reduction of low-grade chronic inflammation. Moreover, the biotransformation of flavanols by gut bacteria increases their bioavailability generating a number of metabolites with potential to affect human metabolism, including during metabolic diseases. However, the exact mechanisms by which flavanols act on the microbiota and immune system to influence health and disease remain unclear, especially in humans where these connections have been scarcely explored. This review seeks to summarize recent advances on the complex interaction of flavanols with gut microbiota, immunity and inflammation focus on metabolic diseases.

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