Contributions of microRNAs to peripheral insulin sensitivity

Endocrinology ◽  
2021 ◽  
Author(s):  
Kang Ho Kim ◽  
Sean M Hartig

Abstract An extensive literature base combined with advances in sequencing technologies demonstrated microRNA levels correlate with various metabolic diseases. Mechanistic studies also establish microRNAs regulate central metabolic pathways and thus play vital roles in maintaining organismal energy balance and metabolic homeostasis. This review highlights research progress on the roles and regulation of microRNAs in the peripheral tissues that confer insulin sensitivity. We discuss sequencing technologies used to comprehensively define the target spectrum of microRNAs in metabolic disease that complement studies reporting physiologic roles for microRNAs in the regulation of glucose and lipid metabolism in animal models. We also discuss the emerging roles of exosomal microRNAs as endocrine signals to regulate lipid and carbohydrate metabolism.

2017 ◽  
Vol 233 (3) ◽  
pp. R145-R171 ◽  
Author(s):  
Rachel Botchlett ◽  
Shih-Lung Woo ◽  
Mengyang Liu ◽  
Ya Pei ◽  
Xin Guo ◽  
...  

Obesity is an ongoing pandemic and serves as a causal factor of a wide spectrum of metabolic diseases including diabetes, fatty liver disease, and cardiovascular disease. Much evidence has demonstrated that nutrient overload/overnutrition initiates or exacerbates inflammatory responses in tissues/organs involved in the regulation of systemic metabolic homeostasis. This obesity-associated inflammation is usually at a low-grade and viewed as metabolic inflammation. When it exists continuously, inflammation inappropriately alters metabolic pathways and impairs insulin signaling cascades in peripheral tissues/organs such as adipose tissue, the liver and skeletal muscles, resulting in local fat deposition and insulin resistance and systemic metabolic dysregulation. In addition, inflammatory mediators, e.g., proinflammatory cytokines, and excessive nutrients, e.g., glucose and fatty acids, act together to aggravate local insulin resistance and form a vicious cycle to further disturb the local metabolic pathways and exacerbate systemic metabolic dysregulation. Owing to the critical role of nutrient metabolism in controlling the initiation and progression of inflammation and insulin resistance, nutritional approaches have been implicated as effective tools for managing obesity and obesity-associated metabolic diseases. Based on the mounting evidence generated from both basic and clinical research, nutritional approaches are commonly used for suppressing inflammation, improving insulin sensitivity, and/or decreasing fat deposition. Consequently, the combined effects are responsible for improvement of systemic insulin sensitivity and metabolic homeostasis.


Open Biology ◽  
2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Chang Guo ◽  
Chenxi Wang ◽  
Xia Deng ◽  
Jianqiang He ◽  
Ling Yang ◽  
...  

ANGPTL8 is an important cytokine, which is significantly increased in type 2 diabetes mellitus (T2DM), obesity and metabolic syndrome. Many studies have shown that ANGPTL8 can be used as a bio-marker of these metabolic disorders related diseases, and the baseline ANGPTL8 level has also been found to be positively correlated with retinopathy and all-cause mortality in patients with T2DM. This may be related to the inhibition of lipoprotein lipase activity and the reduction of circulating triglyceride (TG) clearance by ANGPTL8. Consistently, inhibition of ANGPTL8 seems to prevent or improve atherosclerosis. However, it is puzzling that ANGPTL8 seems to have a directing function for TG uptake in peripheral tissues; that is, ANGPTL8 specifically enhances the reserve and buffering function of white adipose tissue, which may alleviate the ectopic lipid accumulation to a certain extent. Furthermore, ANGPTL8 can improve insulin sensitivity and inhibit hepatic glucose production. These contradictory results lead to different opinions on the role of ANGPTL8 in metabolic disorders. In this paper, the correlation between ANGPTL8 and metabolic diseases, the regulation of ANGPTL8 and the physiological role of ANGPTL8 in the process of glucose and lipid metabolism were summarized, and the physiological/pathological significance of ANGPTL8 in the process of metabolic disorder was discussed.


Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1004
Author(s):  
Sonia Kiran ◽  
Vijay Kumar ◽  
Santosh Kumar ◽  
Robert L Price ◽  
Udai P. Singh

Obesity is characterized as a complex and multifactorial excess accretion of adipose tissue (AT) accompanied with alterations in the immune response that affects virtually all age and socioeconomic groups around the globe. The abnormal accumulation of AT leads to several metabolic diseases, including nonalcoholic fatty liver disorder (NAFLD), low-grade inflammation, type 2 diabetes mellitus (T2DM), cardiovascular disorders (CVDs), and cancer. AT is an endocrine organ composed of adipocytes and immune cells, including B-Cells, T-cells and macrophages. These immune cells secrete various cytokines and chemokines and crosstalk with adipokines to maintain metabolic homeostasis and low-grade chronic inflammation. A novel form of adipokines, microRNA (miRs), is expressed in many developing peripheral tissues, including ATs, T-cells, and macrophages, and modulates the immune response. miRs are essential for insulin resistance, maintaining the tumor microenvironment, and obesity-associated inflammation (OAI). The abnormal regulation of AT, T-cells, and macrophage miRs may change the function of different organs including the pancreas, heart, liver, and skeletal muscle. Since obesity and inflammation are closely associated, the dysregulated expression of miRs in inflammatory adipocytes, T-cells, and macrophages suggest the importance of miRs in OAI. Therefore, in this review article, we have elaborated the role of miRs as epigenetic regulators affecting adipocyte differentiation, immune response, AT browning, adipogenesis, lipid metabolism, insulin resistance (IR), glucose homeostasis, obesity, and metabolic disorders. Further, we will discuss a set of altered miRs as novel biomarkers for metabolic disease progression and therapeutic targets for obesity.


2006 ◽  
Vol 91 (11) ◽  
pp. 4287-4294 ◽  
Author(s):  
Tania S. Burgert ◽  
Sara E. Taksali ◽  
James Dziura ◽  
T. Robin Goodman ◽  
Catherine W. Yeckel ◽  
...  

Abstract Background: Concurrent with the rise in obesity, nonalcoholic fatty liver disease is recognized as the leading cause of serum aminotransferase elevations in obese youth. Nevertheless, the complete metabolic phenotype associated with abnormalities in biomarkers of liver injury and intrahepatic fat accumulation remains to be established. Methods: In a multiethnic cohort of 392 obese adolescents, alanine aminotransferase (ALT) levels were related with parameters of insulin sensitivity, glucose, and lipid metabolism as well as adipocytokines and biomarkers of inflammation. A subset of 72 adolescents had determination of abdominal fat partitioning and intrahepatic fat accumulation using magnetic resonance imaging. Findings: Elevated ALT (>35 U/liter) was found in 14% of adolescents, with a predominance of male gender and white/Hispanic race/ethnicity. After adjusting for potential confounders, rising ALT was associated with reduced insulin sensitivity and glucose tolerance as well as rising free fatty acids and triglycerides. Worsening of glucose and lipid metabolism was already evident as ALT levels rose into the upper half of the normal range (18–35 U/liter). When hepatic fat fraction was assessed using fast magnetic resonance imaging, 32% of subjects had an increased hepatic fat fraction, which was associated with decreased insulin sensitivity and adiponectin, and increased triglycerides, visceral fat, and deep to superficial sc fat ratio. The prevalence of the metabolic syndrome was significantly greater in those with fatty liver. Interpretation: Deterioration in glucose and lipid metabolism is associated even with modest ALT elevations. Hepatic fat accumulation in childhood obesity is strongly associated with the triad of insulin resistance, increased visceral fat, and hypoadiponectinemia. Hence, hepatic steatosis may be a core feature of the metabolic syndrome.


1992 ◽  
Vol 127 (4) ◽  
pp. 344-350 ◽  
Author(s):  
Allan A Vaag ◽  
Henning Beck-Nielsen

The effect of prolonged treatment with Acipimox on in vivo peripheral insulin sensitivity, and on glucose and lipid metabolism, was investigated in patients with NIDDM in a double-blind study. Twelve NIDDM patients were randomized to treatment with either placebo or Acipimox in pharmacological doses (250 mg×3) for three months. Fasting plasma glucose, insulin, C-peptide and HbA1c concentrations were unaffected after three months of acipimox treatment. However, fasting plasma non-esterifled fatty acid (NEFA) concentrations were twofold elevated after Acipimox treatment (1.34±0.09 vs 0.66±0.09 mmol/l; p<0.05). Despite this, repeated acute Acipimox administration after the three months' treatment period enhanced total insulin-stimulated glucose disposal to the same extent as acute Acipimox administration before the treatment period (367±59 vs 392±66 mg·m−2·min−1, NS; both p<0.05 vs placebo glucose disposal) (267±44 mg·m−2·min−1). In conclusion, insulin resistance or tachyphylaxis towards the effects of Acipimox on insulin stimulated glucose disposal was not induced during prolonged Acipimox treatment. The lack of improvement of blood glucose control in the patients with NIDDM may be due to the demonstrated rebound effect of lipolysis.


1989 ◽  
Vol 257 (5) ◽  
pp. E772-E781 ◽  
Author(s):  
E. N. Bergman ◽  
S. S. Reulein ◽  
R. E. Corlett

To assess the mechanisms of insulin resistance in the ruminant, severe and adult-onset obesity was produced in Dorset ewes by overfeeding a high-energy ration over a 1- to 2-yr period. Body weights increased to 100 kg compared with 50 kg in lean control sheep; significant hyperinsulinemia (40 +/- 4 vs 10 +/- 1 microU/ml) also developed as did a moderate hyperglycemia (62 +/- 2 vs. 52 +/- 1 mg/100 ml). Tissue sensitivity and responsiveness to insulin were then determined in both obese and lean sheep by the euglycemic glucose-clamp technique. Insulin was infused at eight different rates from 0.2 to 50 mU.kg-1.min-1 and [6-3H]-glucose was infused for measurement of glucose kinetics. The mean dose-response curves for glucose utilization and clearance rates were displaced to the right in obese compared with lean sheep. As a result, the half-maximally effective insulin concentrations usually were elevated two- to fourfold, indicating decreased insulin sensitivity in obese sheep, and this is consistent with decreased insulin receptors in peripheral tissues. On the basis of fat-free body weight, the maximal glucose responses, however, were not significantly different between obese and lean sheep, indicating that postreceptor defects do not exist in muscle tissue. Furthermore, lean ruminants are more resistant to insulin than are humans, but this resistance seems only because of the sheep's decreased responsiveness to insulin and thus only because of postreceptor insulin effects in peripheral tissues.


2011 ◽  
Vol 300 (4) ◽  
pp. R835-R843 ◽  
Author(s):  
Donato A. Rivas ◽  
Sarah J. Lessard ◽  
Misato Saito ◽  
Anna M. Friedhuber ◽  
Lauren G. Koch ◽  
...  

Chronic metabolic diseases develop from the complex interaction of environmental and genetic factors, although the extent to which each contributes to these disorders is unknown. Here, we test the hypothesis that artificial selection for low intrinsic aerobic running capacity is associated with reduced skeletal muscle metabolism and impaired metabolic health. Rat models for low- (LCR) and high- (HCR) intrinsic running capacity were derived from genetically heterogeneous N:NIH stock for 20 generations. Artificial selection produced a 530% difference in running capacity between LCR/HCR, which was associated with significant functional differences in glucose and lipid handling by skeletal muscle, as assessed by hindlimb perfusion. LCR had reduced rates of skeletal muscle glucose uptake (∼30%; P = 0.04), glucose oxidation (∼50%; P = 0.04), and lipid oxidation (∼40%; P = 0.02). Artificial selection for low aerobic capacity was also linked with reduced molecular signaling, decreased muscle glycogen, and triglyceride storage, and a lower mitochondrial content in skeletal muscle, with the most profound changes to these parameters evident in white rather than red muscle. We show that a low intrinsic aerobic running capacity confers reduced insulin sensitivity in skeletal muscle and is associated with impaired markers of metabolic health compared with high intrinsic running capacity. Furthermore, selection for high running capacity, in the absence of exercise training, endows increased skeletal muscle insulin sensitivity and oxidative capacity in specifically white muscle rather than red muscle. These data provide evidence that differences in white muscle may have a role in the divergent aerobic capacity observed in this generation of LCR/HCR.


2014 ◽  
Vol 995 ◽  
pp. 1-27 ◽  
Author(s):  
Mahbuba Rahman ◽  
M. Rubayet Hasan

Pentose phosphate (PP) pathway, which is ubiquitously present in all living organisms, is one of the major metabolic pathways associated with glucose metabolism. The most important functions of this pathway includes the generation of reducing equivalents in the form of NADPH for reductive biosynthesis, and production of ribose sugars for the biosynthesis of nucleotides, amino acids, and other macromolecules required by all living cells. Under normal conditions of growth, PP pathway is important for cell cycle progression, myelin formation, and the maintenance of the structure and function of brain, liver, cortex and other organs. Under diseased conditions, such as in cases of many metabolic, neurological or malignant diseases, pathological mechanisms augment due to defects in the PP pathway genes. Adoption of alternative metabolic pathways by cells that are metabolically abnormal, or malignant cells that are resistant to chemotherapeutic drugs often plays important roles in disease progression and severity. Accordingly, the PP pathway has been suggested to play critical roles in protecting cancer or abnormal cells by providing reduced environment, to protect cells from oxidative damage and generating structural components for nucleic acids biosynthesis. Novel drugs that targets one or more components of the PP pathway could potentially serve to overcome challenges associated with currently available therapeutic options for many metabolic and non-metabolic diseases. However, careful designing of drugs is critical that takes into the accounts of cell’s broader genomic, proteomic and metabolic contexts under consideration, in order to avoid undesirable side-effects. In this review, we discuss the role of PP pathway under normal and abnormal physiological conditions and the potential of the PP pathway as a target for new drug development to treat metabolic and non-metabolic diseases.


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